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1 


1 

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JULY 

1968 


3 


1 


:2'B 




S 




J 



the STEPTRON 

electronic stop watch 
for the photographer 





SOLDERING EQUIPMENT 



FOR 

THE 

RADIO 

CONSTRUCTOR 




LLUSTRATED 

-y detachable 

BIT INSTRUMENT 
(List No. 64) 

IN 

PROTECTIVE 

SHIELD 

WITH 

ACCESSORIES 

(List No. 700) 



FOR CATALOGUES APPLY DIRECT 

ADCOLA PRODUCTS LTD. 
ADCOLA HOUSE 
GAUDEIM ROAD 

Telephone: 

LONDON, S.W.4 01 622 0291/3 

Telegrams: "S L J 1 NT" LO N D N SW4 



Amatfiip pAd 



CHAS. H. YOUNG LTD. 



MIDLAND AGENTS FOR 

EDDYSTONE 

Receivers & Components 




EDDYSTONE EC10 

Sensational ALL-TRANSISTOR Communications 

Receiver, for use in the home, caravan, car or boat, etc, 

LiSt Price £53 HLP. Facilities — Part Exchanges 
Write for brochure & fuff details. 

170-172 CORPORATION STREET 
BIRMINGHAM 4 

Telephone: 021-236-1635 



17in.— £11,10.0 
19in SLIMLINE 
SO BEL— 24Gns. 



TWO-YEAR GUARANTEE 
EX-RENTAL TELEVISIONS 



FREE ILLUSTRATED 

LIST OF TELEVISIONS 

17*— 19"— 2T-23" 

WIDE RANGE OF MODELS 

SIZES AND PRICES 
DEMONSTRATIONS DAILY 

~TWo"- YE AfTgUAR AN TE ED 
TUBES 100% REGUNNED 

14in.— 69,6 17in.— S9/6 
21 In. and ALL SLIMLINE TUBES 99,'6 

EXCHANGE BOWLS. Carr, 10/6 

Ex. MAINTENANCE TESTED TUBES 

1 7ln. — 35/-. Carr.5/- (not slimline) 




COCKTAIL STEREOGRAM CABINET £25 

Poiished walnut veneer with elegant 
glass fronted cocktail compartment, 
padded. Position for two 10. n. ellip- 
tical speakers. Record storage 
space. Height 35Jin., width S2jln., 
depth 14jin. Legs 1 gn. extra. 
OTHER MODELS. SEND FOR 
FREE LIST 

"TRANS ISTOR CH AS SI 3 
D1 59/6 

6 Transistors, LW/MW, Telescopic 
Aerial. Brand New. Famous British 
Manufacturer. {LESS SPEAKERS). Dla. ~1\" % 3f", P. & P. 4/6, 
TRANSISTOR CHASSIS D2 69/6. 

8 Transistors, LW/MW. Brand New, Famous Manufacturer. (LESS SPEAKERS 

10Q). Dla. 9i"x5". P. 4 P. 4/6. 

TRANSISTOR CASES 19/6. Cloth covered, many colours. Size 9i" it 61" x 3i". 

P. i P. 4,'6. Similar cases in plastic 7/6. 

AUTO CHANGER RECORD PLAYER CABINETS 59/6. P. 4 P. 7/6. 

SINGLE PLAYER CABINETS 19/6. P. 4 P. 7/6. 

TV TURRET TUNERS 5/-. New, less valves. Press button models 19/6. 

P. & P. 4/B. 




DUKE & CO. (LONDON) LTD. 

621/3 Romford Road, London, E12 Tel. 01-478 6001/2/3 




**««B»„,««»^ 



with Wharfedale's Unit 3 Speaker kit 

Wharfedale have designed a new genuine high 
fidelity system that you can build yourself. With 
the Unit 3 Kit you get: an 8" speaker (with a 
magnetic field of 1 2,000 oersteds) which covers 
the bass and middle ranges; the new Wharfedale 
tweeter with acoustiprene dome; an electrical 
cross-over unit; acoustic wadding, wiring, etc., 
and a complete assembly instruction leaflet, in 



fact, everything you need to build a compact 
speaker system. 

You can build the Unit 3 Kit into one of two 
cabinet sizes. In the smaller cabinet the system 
will give a faithful and rich reproduction of all 
musical sounds from 65 - 17,000 Hz. The larger 
cabinet increases the range from 40 - 1 7,000 Hz. 



WHARFEDALE 



RANK WHARFEDALE LTD., IDLE, BRADFORD, YORKSHIRE. 




153 




VIKING AMPLIFIER 

50 WATT AMPLIFIER 

An extremely reliable general 
purpose valve amplifier. Its rug- 
ged construction yet space age 
styling and design mak^s it by far 
the best value for nionev. 
TECHNICAL SPECIFICATIONS 
4 electronically mixed channels, with 2 
inputs per channel, enables the use of 8 sep- 
arate instruments at the same time. The volume controls for each channel 
are located directly above the corresponding input socket 1 ; 
SENSITIVITIES AND INPUT IMPEDANCES 

Channel 1 4mV at 470 K \ These 2 channels (4 inputs) are suitable for 
Channel 2 4naV at 470K j microphone or guitars. 
Channel 3 200m V at Ira \ Suitable for most high output instruments 
Channel 4 200m V at itn J (gram, tuner, organ etc.). 
Input sensitivitv relative to IOw output. 
TONE CONTROLS ARE COMMON TO ALL INPUTS 
Bass Boost + 12dB at 60 Hz's. Bass Cut — I3dB at 60 Hz/s. 

Treble Boost -lldB at 15 KHz/s. Treble Cut -I2dB at 15 KHz/s. 
With bass and treble controls central — 3dB points are 30 Hz/s and 
20 KHz/s. 
POWER OUTPUT 

Tor speech and music 50 watts mis. 100 watts peak. 
For sustained music 45 watts rms. S)0 watts peak. 
For sine wave 3S'5 wat:s rnis. Nearly SO watts peak. 
Total distortion at rated output 3-2% \ . T ,„ 
Total distortion at 20 watts 015% j lttii *' s 

< 'in !"i: in mulch into S or 15 ohms speaker system. 
NEGATIVE FEED BACK 20dB at 1 KHz/s. 
SIGNAL TO NOISE RATIO OOdB. 
MAINS VOLTAGES 

Adjustable from 200-250 v A.C. 50-60 Hz/s. 
A protective fuse is located at the rear of unit. 
VALVE LINE UP 

Double purpose ECC83 x 3, EL34 x 2 and 
GZ34. 



Price 

27 gns 

P & P 20/- 



FOUR PLUS FOUR Stereo Amplifier 



A superb high quality, yet inex- 
pensive stereo amplifier. Due to 
the great demand we are now able 
to offer this precision made instru- 
ment at a fantastically low price. 
The high quality, reliability and 
styling has been maintained in 
spite of its low price. 
SPECIFICATIONS 
Elegant styled cabinet (sizes 10* 
wide 5* high 8J* deep) in black 
rexine and woodgrained sides. 
Brushed aluminium front panel 
with contrasting black /silver 
knobs. 
CONTROLS 

Stereo/Mono switch. Gram/Aux 
switch. Volume left. Volume right. 
Treble (cut and lift). Bass (cut and 
lift). Separate on/off switch. Neon 
pilot indicator. 
INPUTS AND OUTPUTS 
(per channel) 

Gram, aux, tape out and speaker 
out, A switched mains socket is 



also provided at the rear of unit. 
Employs Mullard valves throughout. 
ECC83 and 2 z ECL86 with a metal 
bridge rectification. 
TECHNICAL SPECIFICATIONS 
Gram sensitivity 40mV at 1 KHz, 
Aux sensitivity 50mV at 1 KHz, 
[Sensitivities arc given for rated out- 
put), 4 watts r.m.s. 
(8 watts r.m.s. in 
monaural position). 
Output matches in- 
to standard 3 ohms 
speaker system. 
Suitable 10" x 6" 
speakers are avail- 
able at 29/6 each, plus 5/- p. & p. 
Bass control at 100 Hz lift + SdB 
cut - lOdB. Treble control at 
10 KHz lift + SdB cut - 13dB. 
Total harmonic distortion 0-35% 
at 3 watts and 2% for rated output 
at 1 KHz. Negative feedback 1MB 
at 1 KHz. Mains supply 220-250 V 
A.C, 50-60 Hz. 



Price 

13 gns 

p& p t$/~ 



REDUCE SPEED NOW with a speedex 

infinitely variable electronic speed controller for vour electric power drill. 
Varies the speed of all power tools (up to 600 W) between 12 r.p.ti]. and 
maximum r.p.m. 

Instantly adjustable with simple single control overriding switch for 
instant maximum speed. Simply connected into lead of* power tool 
Only 25/- plus 3/0 P. & P. 



GEO KETTLE ELEMENT 

3.000W WITH AUTOMATIC EJECTION 

200 2-10 v. Size of hole required 1A" 
List Price 32/-. Our PRICE 
15/-. P. & P. 1/8. 




RADIO & TV COMPONENTS (Acton) LTD 

21c High Street, Acton, London, W3 

Shop Hours 9 a.m. — 6 p.m. Early Closing Wednesday 

Goods tint despatched oultfde V.E. Termt C.W.O. 
AH enquiries Stamped Addressed Envelope 



Also at 323 EDGWARE ROAD, LONDON, W.2. Personal shoppers only. 
Early Closing Thursday. All orders by post to our Acton address. 




POCKET MULTI- METER 

Size 3| x 2£ x l|tn Meter size 2J x 1 jln Sensitivity 1000 
O.P.V, on both A.C. and D.C. volts, 0-15, 0-100, 0-1000 
D.C. current 0-1 50mA. Resistance 0-100kn. Complete. 
wire test prods, bautrv anil 1UI iiiMnirtioni, 42/0. P. A P. 
3/B. FREE GIFT lor limited period only. 30 watt Electric 
Soldering Iron value 16/- to every purchaser of the Pocket 
Multi-Meter. 



CYLDON 
U.H.F. TUNER 

Complete with PCS8 and PCS6 
Valves. Full variable tuning. 
New and unused. Size 4} x aj x 
I Jin. Complete with circuit 
diagram. 3g/_ P- * p- 3/fi 




THREE-IN-ONE HI-FI 
10 WATT SPEAKER 

A complete Loud Bpeak«r system on one 
frame, combining three matched ue ramie 
magnet speakers with a Jew loss cross, 
over network. Peak handling power 
10 watts. Impedance 19 ohms. Flux 
density 11,000 gauss. Resonance 40- 
60e.'s. Frequency Mnm 50c/s to SOkcis. 
8ise 131 i 8V le i 4J inches. By famous 
manufacturer. List Price it. Our price 
69/6 plus 3/6 P. & P. 



600 mW FOUR TRANSISTOR AMPLIFIER 

Features N.PjN. and P.N.P, complementary symmetrical output stara, 
A-a* *■ x £ Speaker. Output impedance 12 ohms frequency response 
t Pt"«ts 90 c/s and 12 Kc/s. Price 19/6 plus 1/- P. & P. 7 x 4'Spealt.er 
to suit, 13/6 plus 2/- P. & P. 



Ik watt ALL TRANSISTOR AMPLIFIER 

AC mams 240V. Size 7" x *i" x If". Frequency response J00 c/s— 10 Kc/s 
Semi conductors, two. OC 75's two AC 128's and two stabilizers AA120 
lone and volume controls on flying leads. £2.10.0 plus P & P 3/tf 
Suitable 8" x 5" 10,000 line high flux speaker, 18/6 plus 2/- P & P 



M W TRANSISTORISED 
SIGNAL GENERATOR 



Size 5i x 3J x 1 Jin. For IF and BF alignment and AF 
output, 700 c,'s frequency coverage 480 fcoft to 2 mc/a 

m switched frequencies. Meat for alignment to our 

tlegantgeveiiaiid MiL.itLLc.Itii Hi. ;•!,,! tr-,tv.l. /tn C 

P. tF.8(«. ,3 /° 




H' 



FIRST QUALITY P.V.C. TAPE 



Std. 
Std. 

:r l.p. 

5F L.P. 
7" L.P. 
5i" CP. 



850ft 9/- 5" L.P. 

1200ft H/6 :r T.P. 

240ft. 



850ft. 

lilHtft. 

.. 4/- 5" T.P, ISOOft. 

12O0ft 11/6 5J- T.P. 2400ft. 

1800ft 18/6 7* T.P. 3000ft. 

1800ft 18/6 4* T.P. 900ft. 

P. & P, on each 1/6, 4 or more post free. 



.10/6 
.10/6 

.25/6 
.32/6 

. 42 6 
.15/- 



THE RELIANT IOW SOLID-STATE HIGH QUALITY AMPLIFIER 

SPECIFICATIONS 

Output— 10 watts KMS Sine-wave Output Impedance— 3 to 4 ohms 

la watts it MS Ma?:c-power 
Inputs— 1. • 3j»tr nfoltoy ^ Tone Controls— Treble control range ± ISdB at 10KTT2 



2. -gram/radio aoOruV 



Bass iiootrol range ± 1 3d IS at hm u I i 



-. e , uu/ ._ ul wuiu>uT uaag tnairoi range i UraBat I tin 1 12 

Frequency Rtsponse— (with tone controls central) Minus 3dB point- arc 20H2 and 40KH2. 
Signal to Noise Ratio— better than — 80.IR. Transistors— i silicuji I'lanar tvne and 3 
i:,:v:u:n.;ini, type. MoSt.s input 220 —250V. A.t". SIzO ..I ObaaStl HI ■■' ; ■ 

A.C. Maiii-<, ■Jou-'jjUV. Tor nst with Std or L.P. reran?,, :mniwii m.ii t iin™i« :,li ,'i^k. -.",,( 
pick-ups and mikes. Separate bass and treWc lid contmr. Tm inputs -.villi ,■ mm.l s ,-r siri-iu 
KlS^2i«^^ d , t , C9 i C p- 8 " X 5 " 3 P eake "o8iiit price 14/6 1. 1' is I'll f. * lv<vvstalinike 

Ui Hill 111 fa li mi I.'ti P. <t P. DDT/to he c a _!„.. £ > n ^ *. 



PRICE «S.5.0 plus 0/- P. a P. 



LESLIE TREMOLO SPEAKER UNIT 



Model IOCS. Made in U.S.A. by Electro Music Corp., Pasadena, (lain. Cmnpte-'c vdUi 8" 
(i..hn, M.vryy lUiiy Loud Sacakc-r. (Larger Sm-aker may be.'itl.'d «ii horn. ; r,.i J: ,r m mrl „ ra i 
change ). Dimensions: baffle size 18^" X 19*. Rotorsize 1C*. A.C. mair;s I Id ^'ii-v.iii 5u ,-n 

PRICE *30liUiiS2 P. 4?! 



suitable for organs. 



50 WATT POWER AMPLIFIER 

Manufactured by Livingstone Laba. at a cost price of £90, In two unit! Amplifier size 

16i " £ Li 7 ; 11 ' 3 ! ' i1 '^ "^ Ul " x lr x 4 "' °" ttn,t into ]5 onm Speaker. Trambiturs 

,-i M h! (IWls. I«o2i;s,4.soniitivity IV. EMS at ,JK it;,,,,; „„„„1 1KC . r.w.r K,-, pil i,.se 

5112-ielvUj; (;i0 watts). Ideal for Tannoy Systems or organ, where con.slut,; use Is i>.*sciiti:.l 

^ PRICE 28gns. plus £2 P. A P." 



ANTI-THIEF CAR BURGLAR ALARM 

The Melguard Safermatic consists of an electrical device housed in sinat] muul boi 4" X 2* 
X IJ", which taaa been designed and developed to pruvide pmtection reuulred by the 
;u-.'ra.:.ru in,-['.r;s' at an teaaaaSe coat. Ostag tlaa system, a:, nlnrm .,,,.1 Bu tmmoU&ad 
condition is set automatically as soon as you park the car. Should you leave the kev in the 
IgnJUun. nu one but yon can drive the car away. Upon entering the vehicle the method of 
starting the car is by switching on the ignition, depressing two hidden switches and tfrmri- 
tancously operating the starter. Location ol the switches is known onlv to you Should the 
ttl*rm be set uft it can he stopped by following the normal startup in-,.,-!-diir.- I'..r i'2V 
oiiirntion. List price 70;6, onr price 28/8 p?us "IS F. & p. Full ea«y-K,-foHow lu^tructiona 



EXTRACTOR FAM 




AC Mains 
230/250 v. 
complete, 
with pull 
s w i t c fa . 
Size 6" x 
6" x 4". 
Price 27/6 
plus 5/- 
P. & P. 




AC MAINS 

MOTOR 
1400 R.P.M. 

230/250v 

PRICE 

9/6 

P. & P. 3/- 



154 



SIKTS; I NEWi m Dorset 



ei 



Its great versatility ran- 
ges from : A simple inter- 
com, to a modern HI-FI 
STEREO AMPLIFIER (2 
are required for Stereo >. 

The X101 , ia e. brilliant 
now addition to our 
highly successful range 
of products. Its profes- 
sional performance and 
advanced solid-state cir- 
cuitry techniques en- 
sures reliability, com- 
bined with high fidelity 
reproduction at AN 
UPJBEATABLE PRICE, 
SPECIFICATIONS 
R.M.S. Power Output: 13 W (music power), 10 W (Sine Wave). 
Sensitivity; for rated output Ira? into 3 K ohms load. 
Frequency Response: minus 3dB points are 20 Hz and 40 KHz. 
Total Distortion: at IKHz for rated output 1-5%, for 5 W output 

0-35%. 
Output Impedance: 3 ohms (3-15 ohms may be used). 
Supply Voltage: 24 VD.C. at 800 mA (6-24 V may be used.) output at 

14 V D C. supply with 3 ohms speaker. 7 watts. 
Size:2rx3-xl B / ls *, 

The fully comprehensive instruction manual does not only show the 
basics, such as circuit diagram and connections, but also gives 
practical easy-to-imderstand detailed information about the X10I. 
Standard equalisation networks axe given for most types of con- 
ventional inputs. They include: Tape Head, Mag, P.U., Xtal P.U., 
Tuner, Mic, etc. AQ MS , o, R „ ^ ,, 
Built & Tested *S»/0 + 2/BP. &p. 



Control assembly: (Including resistors and capacitors). 

1. Volume: PRICE 5/-. 2. Treble: PRICE 5/-. 

3. Comprehensive bass and treble: PRICE 10/-. 
The above 3 items can be purchased for use with the X101. 



POWER SUPPLIES FOR THE XI 01 



P101M (lor mono) 
P. & p. 2/6 



35/- 



P101 S (for stereo) AOIfi 
P. &p. 216 **"£/« 



CAN BE USED AS 
BABY ALARM 



600 milliwatt solid stats 7 transistor 

plus diode and thermistor. Completely 

moduli scil high quality portable radio 

losturing complementary NPN and PNP output 

stage. The comprehensive easy-to-follow drawings 

■applied make this the sasiest-ever transistor radio set 

Ot parts, with the following features ; 

• Simple connections to only 8 tags on the K.F./f.P, 
module, 3 I.F, etagee. osc. coll and 3 transistors which 
with their associated components are completely wired. 

■ Only 4 connections on the A.¥. module to complete the 4 
transistor 000 milliwatt solid state amplifier. 

• Pre-allgned B.F./I.F. module built and tested, 

• A.F. module built anil tested. 

• Fully tunable over M.W. and L.W. bands. M W 
040-1S40 Kc/s {5B7-183 metres). L.W. 150-275 Kc/s 
(2000-1100 metres). 

• Intermediate Frequency 470 Kc/s. 

• s,-s ,itivity: stvw, «l i ttJefi to mtoorolta utni >r mimu ,idb nv a i 3M 
Kc/s 40 microvolt plus or minus 4dB, 

• High Q interna,! ferritc rod aerial on both wavebands. 

• (!j:is<'H Hi, dutbedon^mtttw «v.h!:h,:-im;.-<:. rwntiailedbeatstabassaoi) 
Uaas B output stage ensures long battery life. Cm-rent drain is proportional 
to Use output level. Total current drain of the receiver under no signal 
conditions is 10-12 mA. At reasonable Ustenlng level 20-30 mA 

• Extension sockets lor car aerial Input, tape recorder output (Independent 
of volume control) and Externa! Speaker. 

• AU orapmunrt" (except speaker) mount on the printed circuit board. Easy- 
to-follow Instructions, Slie of cabinet 12in. long Sin. high and Sin. deep 

• Finger-Up controls. 

Special Offer— Power Supply Kit to purchasers o! Dorset Portable Eadio jarta 



pins 7/6 postage 

and packing. 

Circuit and 

parti list 2/6 

free with parts. 



PR 101 Nl 



MONAURAL PRE- AMP 
& CONTROL UNIT 



Particularly suitable for use with the X101 if a ready-bailt, compre- 
hensive, multi-input system is desired. 

CONTROLS 

Selector Switch, Tape Speed Equalisation Switch (3f and 7t 
l.p.s.). Volume. Treble, Bass, 3 position scratch filter and 3 
position rumble filter. 

SPECIFICATION 

Sensitivities for 200 m? output at 1 KHz. 

Tane Head: 3 mV (at 3} i.p.s.) ltadlo; 100 mV 

Mag. P.U.; 2mV Aux.s 100 mV 

Cer. P.U.: 80 mV 

Taoe/Ree, Output: 100 mV 

Equalisation for each input is correct to within ±2dB CR.I.A A) 

from 20 Ha to 20 KHz. 

Tone Control Range; Bass -!-13dB at 60 Hz 

Treble =14dB at 15 KHz 
Total Distortion: (for 200 mV output) < 02% 
Signal Xoise: >— 60dB 
Supply Voltage: 24 V D.C . 

79 /g plus 2/8 p. & p. 



A STEREO VERSION (PR101/S) WILL BE ANNOUNCED 
SHORTLY 



HIGH QUALITY 
SOLID-STATE 
AMPLIFIER (MONO) 



SPECIFICATION 

Switched inputs for: Tape Head, Mas. P.U., Cer. P.U., Radio and 
Aux. Mains Input: 220-250 V A. C. SO Hz, 

THE CLASSIC IS THE COMBINATION OF THE ABOVE DES- 
CRIBED ITEMS (X101. P101/M AND PR101/M) ON ONE COMMON 
CHASSIS: ITS PERFORMANCE AND SPACE-AGE STYLING 
MAKE IT THE IDEAL CHOICE FOR THE 
VALUE-CONSCIOUS HI-FI ENTHUSIAST. 
Size 122* long 41* deep 22' high. Teak finished case, 
p. & p. free 



-£i-^lVJjy Oil IUUX v 

8gns 



C0M8MP PORTMU 
| 3M/CAMU910 



Buy yourself an easy to build 7 
translator radio and save at least 
£10.0,0, Now you can build tMs 
superb transistor superhet radio 
for under £4.10.0. No one else can 
offer such a fantastic radio with so 
matiy de luxe star features. 



SPECIAL OFFER 




-jr De luie wooden, cabinet size 

PO WEE SUPPLY KIT 12 ** * 81 " x 3i ' m 
To purchasers of 'Elegant * Horizontal easy to read tuning 
Seven* parts, incorporate scale printed grey with black 
letters, size 11|* x 2*. 
ir High 'Q' ferrlte rod aerial. 
•fc I.F. neutralization on each 
separate a tage. 
Plus 7/6 P. & I'. Parts List and *k D.C. coupled push pull output 



Ing _ mains transformer! 
rectifier and smoothing 
condenser. A.C. maina- 
200/250 volts. Output 9 v 
100mA. 9/6 estra. 



circuit diagram S/fi i'lLEE with a Use with separate A.C. negative 
parts. feedback, 

■fc Room ailing output 300m W. 
■jkr Beady etched and drilled prl 
construction. 

*£ Fully comprehensive instructions and point-to-point wiring diagrams, 
■^r Car aerial socket, 

>fc Fully tunable over medium and long wave. IGS-333 metres and 12SO-20D0 
metres. 

•fa All components ferrlte rod and tuning assembly mount on printed board, 

<ff 8* P.M. speaker. 

i( Parts list and circuit diagram 2/8, free with parts. 



RADIO & TV COMPONENTS (acton) LTD. 

SIC HIGH STREET . ACTON . LONDON . W3 

OPEN 9 a.m.— tl p.m. INCLUDING SATS. EARLY CLOSING WED 
GOODS NOT DESPATCHED OUTSIDE U.K. TERMS C.W.O. 

All enquiries, stamped addressed envelops 

AH orders by post to be seat to our Acton address 
323 EDGWAEE BO AD, LONDON W3 

Perianal shopperi only. Early elating Thursday. 



155 



FLASH: 



ALL WITH A 



INCREDIBLE MEDIUM WAVE DX RECEPTION A. H. CHILD, W6TYP OF SAN FRANCISCO WHO 
REPORTS? "I COPY STNS. AS LOW AS 1KW IN JAPAN; KOREA, CHINA & TONGA ISLANDS; ONE 
OF THE BEST IS JOHR ON 1Q40KHZ. THEY ARE A GOOD S8 AT 5 A.M. P.S.T." 



JOYSTICK VFA 



SEE IT & BUY IT FROM: 

BATH — Ryland Huntley. 
BIRKENHEAD— D.S. Radio & Electrical 

Stores 108 Chester Street. 
Bl R MING HAM— Cfias. H. Young Ltd. 
BIRMINGHAM — R.S.C. Hi-Fi Centres Ltd. 
BOURNEMOUTH— National RadioSupplies 
BRADFORD— Radio Ham Shack. 
BRADFORD— R.S.C. Hi-Fi Centres Ltd. 
BRIGHTON — Technical Trading Company, 
BRISTOL— R.S.C, Hi-Fi Centres Ltd. 
BURNLEY — Trafalgar Supplies. 
CARDIFF — Wesak Radio. 
CHELTENHAM— Spa Radio Ltd. 
CHESTERFIELD— J. Tweedy Ltd. 
COVENTRY — Swanco Products Ltd 
DARLINGTON— R.S.C. Hi-Fi Centres Ltd. 
DERBY — R.S.C. Hi-Fi Centres Ltd. 
DONCASTER— B. Page. 
EDINBURGH— F. Brown & Co. 
EDINBURGH— R.S.C. Hi-Fi Centres Ltd. 
EXETER — Electrosure Ltd. 
FOLKESTONE— John Gilding Ltd. 
GLASGOW — R.M.E. Surplus Supplies. 
GLASGOW — R.S.C, Hi-Fi Centres Ltd. 
GOREBRIDGE— Gilmour Stewart. 

OR WRITE DIRECT TO: 



HALIFAX— Albert Hind Ltd. 

HARTLEPOOL— The Radio Shop. 

HUDDERSFIELD— Radio Craft (Hudd.) Ltd. 

HULL — R.S.C. Hi-Fi Centres Ltd. 

HULL — Short Wave (Hull) Ltd. 

ILFORD — Radio Developments Ltd. 

LEEDS— R.S.C. Hi-Fi Centres Ltd. 

LEICESTER— S. May Ltd. 

LEICESTER— R.S.C. Hi-Fi Centres Ltd. 

LIVERPOOL— .R.S.C. Hi-Fi Centres Ltd. 

LIVERPOOL — Stephens- James Ltd. 

LEYTONSTONE— R.T. & I. Ltd. 

LONDON — Daystrom Ltd. 

LONDON— G. W. Smith & Co. Ltd. 

LONDON— Lasky's Radio Ltd. 

LONDON— R.T. &l. Electronics Ltd. 

LONDON— Alfred Imhof Ltd. 

LOUGHBOROUGH — Taurus Electrical Ser- 
vices. 

LUTON — Coventry Radio Ltd. 

MANCHESTER — R.S.C. Hi-Fi Centres Ltd. 

MIDDLESBROUGH— R.S.C. Hi-Fi Centres 
Ltd. 

NEWARK — George Francis. 

NEWCASTLE-UNDER-LYME— Sidney T. 
Chadwick. 



Hi-Fi 



NEWCASTLE UPON TYNE— Richley & 
Freeman Ltd. 

NEWCASTLE UPON TYNE— R.S.C. 
Centres Ltd. 

NEWPORT — K. F. Paull Ltd. 

NOTTINGHAM — Pete's Electronics Ltd. 

PLYMOUTH— Radio Parts-Components 
Specialists. 

PORTSMOUTH— Technical Trading Co. 

PURLEY— G3HSC. 

SCARBOROUGH— Derwent Radio Ltd. 

SHEFFIELD— R.S.C. Hi-Fi Centres Ltd. 

SOUTHAMPTON— Technical Trading Co. 

SOUTH SHIELDS— J. R. Gc-ugh Electronics. 

ST. HELENS— Harold Stott Ltd. 

STOKE-ON-TRENT— (see Sidney T. Chad- 
wick, Newcastle- under- Lyme). 

SUNDERLAND— The Red Radio Shop, 

WALSALL — Normal Service Ltd. 

WOLVERHAMPTON— Ling's Radio & Elec- 
tronics 32 Snow Hill. 

WORCESTER— Jack Porter Ltd. 

WORTHING— G.W.M. Radio Ltd. 

WORTHING— Technical Trading Co. 



PARTRIDGE ELECTRONICS LTD. Dept P.W.7 

CAISTER HOUSE, PROSPECT ROAD, BROADSTAIRS, KENT 



TRANSISTORISED 

STEREO HI-FI 

RECORD PLAYER 

I Build your own Hi-Fi Record 
Play,, with the Serenade 
I lull, transistorised empldin; 
I which tomes complete with 
I2.10KB" speakers and the 
llatestOSFM Speed Stereo 
I Mono Record Changer. 
I Advanced solid stale amphtier 
Ioni,H'-leep. 14t-ao^ors 

I Bins * ii,IlieS - sa " a ' a ' B , 

land Treble- 10 watts total 
Lower. Frequency tesporse 

ho 15,000 c/s. 

EASY TO INSTALL 

NO TECHNICAL KNOWLEDGE 

REQUIRED 

loNLYllflGNS. 



+P8.P176 



mUSlIC Bf\MM OFFER! 

"TRANSCONTINENTAL" 

FULLY TRANSISTORISED STEREOPHONIC 

RADIOGRAM CHASSIS 

Complete with 2-10" x 6" speakers and the latest 
BSR Mono Stereo Record Changer -a complete 
radiogram at half normal price ONLY 

10 Watts Total output TLA\^ P* p 

17 Transistors & 10 diodes «JH" 2 GNS. 17 6 
EASILY FITTED NO TECHNICAL KNOWLEDGE NECESSARY 
H.P. available £9:2:6d deposit plus 1B monthly pay- 
ments of £1:15:9d (Total H.P. £41:6:0). 

Send £10 today 



'2B 



H n teim5 mailable. Deposit 
| EL& 1 e.6d and 11 monthly pay- 
Lents oi 38/=il J To ?' "m 
|tt9:17:6iJ r . Send £7:1*0 J 
I today. 





PLFASE Sf 110 ME FREE DETAILS OF YOUR RANEE 



1DD CHASE SIDE, SOUTHGATE. Dep.P78 ' 



LI JL.JCj ¥V 1 a »n-tHl luu !."»« ai"c. suumtjAlt, uep. t- l (j 
L_ _-»A*«a4 LONDON. N 14. TELEPHONE PAL 3733 966b1 




IT'S ALWAYS 
SALE TIME 

AT THE 

WIRECOMP BARGAIN 

CENTRE!!! 

BARGAINS * BARGAINS 
BARGAINS 

There's something for everyone in our vast 

stocks of surplus and first-class 

reconditioned equipment — 

RECORD PLAYERS • HI-FI EQUIPMENT 

TELEVISIONS (from £4 ! I) • RADIOS 

TAPE RECORDERS • W/TALKIES 

SPECIALISTS IN THE UNUSUAL I 

COME AND LOOK TODAY 

48 TOTTENHAM COURT ROAD, W.I 

Telephone 01-636 0647 



156 



S B ELECTRONICS 

A better buy each month 



• BARGAIN PRICE STEREO AMPLIFIER— 13£ GNS. ONLY. 27 gns. retail value. A fully transistorised high fidelity 
stereo amplifier complete in free standing case. Switched input facilities. Socket (1 ) Tape or crystal pick-up. (2) Radio tuner. 
(3) Ceramic pick- up mike. Controls: volume, bass, treble, balance, input selector switch. Stereo/mono switch. Facia plate 
rigid Perspex with black/silver background and matching black edged knobs with spun silver centre. Output 6 watts per 
channel (R. M.S.), 12 watts mono. Free response -f 3d B 20-20,000 hz. Bass boost approx. 1 0-1 2dB. Treble cut 2-1 6dB, 
Approx. negative feedback — 18dB over main amp. 12 months unconditional guarantee. P. & P. 6/-. 



• BARGAIN PRICE STEREO AMPLIFIER— 7 GNS. ONLY. 

16 gns. retail value. A high fidelity unit complete in free standing 
case. Ideal for crystal or ceramic pick-up, tape, radio tuner. Fully 
integrated. Facia plate rigid Perspex. Black/silver matching knobs. 
Output 4 watts per channel R.M.S. 12 months unconditional 
guarantee. P. & P, 5/6, 

• BARGAIN PRICE MONO AMPLIFIER— 7 GNS. ONLY. 

14 gns. retail value, A high fidelity unit providing excellent results 
at all output levels complete in free standing case. Frequency 
response: 30-20.000 c.p.s. — 2dB. Sensitivity 5 mV max. Har- 
monic distortion 0-5% at 1,000 c.p.s. Output 3-8-15 ohms. Input: 
mike, gram, radio tuner, tape recorder. Controls (5): volume, bass, 
treble, mains switch, input selector. Facia rigid Perspex black/silver 
with matching knobs. Output 6 watts R.M.S. (certified). 
12 months unconditional guarantee. P, & P. 5 

• CHANGER DECKS— ALL AT BARGAIN PRICES. 

GARRARD 1000-1025 £6 5 P. & P. 7/6 

GARRARD 2000-2025 £6 15 P. & P. 7/6 

GARRARD 3000-3500 £8 19 6 P. & P. 7/6 

GARRARD AT60 Mk. II ..£12 10 P. & P. 8/6 

GARRARD SL55 £1110 P. & P. 8/6 

GARRARD SP25 Mk. II £1115 P. & P. 8/6 

GARRARD LAB80 Mk. II £23 10 P. & P. 10/6 

GARRARD SRP22 £4.10.0 P. & P. 5/6 

B.S.R. UA25 £6.5.0 P. & P, 7/6 

Plinths to suit all the above, beautifully styled and of No. 1 manu- 
facture. £2.5.0 ONLY. P. & P. 5/-. 

• BARGAIN PRICE A.M. SUPERHET TUNER UNIT— 
6 GNS. ONLY. 12 gns. retail value. Mains operated, fully tran- 
sistorised, ferrite rod aerials. Simply add to any of our amplifiers 
for outstanding results. 12 months unconditional guarantee. 
P. & P. 5/6, 

• BARGAIN PRICE F.M. TUNER UNIT — 8 GNS. ONLY. 

16 gns. retail value. Mains operated, 6 transistor unit. S/M hori- 
zontal dial, 2 I.F. stages, coupled double tuned discriminator 
terminating in I.F. Ample output for all amplifiers. Highly recom- 
mended. 12 months unconditional guarantee. P. & P. 5/6. 

• BARGAIN PRICE L.W./M.W./F.M. TUNER UNIT— 
16 GNS. ONLY. 30 gns. retail value. Mains operated, fully tran- 
sistorised. Output 5 mV, exceptional sensitivity and selectivity on 
all bands. LvV. 180-360 Kc/s. A.M. 600-1400 Kc/s. F.M. 88- 
108 Mc/s. Complete with aerials, 3 band horizontal dial. 12 months 
unconditional guarantee. P. & P. 6/6. 

• BARGAIN— RECORD PLAYER AMPLIFIERS— 47/6 ONLY. 

EL84 output. 2 controls, flying pane!, A.C. mains operated 230- 
240 volt. Non-live chassis. Fully built and tested. 12 months 
unconditional guarantee. P. & P. 2/6. 

• BARGAIN— RECORD PLAYER AMPLIFIER UNIT— 52/6 
ONLY. Complete with valves (UCL82 output). Fully built and 
tested, mounted on board with speaker. Knobs supplied. All leads 
attached ready for instant connection to your turntable. 12 months 
unconditional guarantee. P. & P. 3/6. 

• BARGAIN— RECORD PLAYER CABINETS— 52/6 ONLY. 

Strongly built wooden cabinet — two tone gilt fittings, carrying 
handle. Suitable for any amplifer. Ample space for speaker. Matching 
Garrard or B.S.R. cut-out board supplied free. P. & P. 5/-. 

• BARGAIN— SPEAKERS, STANDARD AND HIGH FI- 
DELITY. 5in. round, 7x4in. elliptical, Sin. round. All 3 ohms. 
ALL ONE PRICE. 15/-. P. & P. 2/6. 



• BARGAIN— E.M.I. 8 x 5in. ELLIPTICAL — OUR PRICE 
27/6 POST FREE. 12,000 lines gauss, 5 wans, Accomax magnet. 
Sold elsewhere at 50/-. 3 or 15 ohms. Brand new with 12 months 
unconditional guarantee. 

• BARGAIN— E.M.I. 13 x. Sin. ELLIPTICAL—OUR PRICE 
47/6 POST FREE. 12,000 tines gauss, 10 watts, Accomax magnet. 
Sold elsewhere at £4. 3 or 15 ohms. Brand new with 12 months 
unconditional guarantee. 

• BARGAIN — BAKER-SELHURST DE-LUXE — OUR PRICE 
£4.19.6 ONLY. 12in. dia. round, 15 watt rating, 12,000 lines gauss, 
Accomax magnet. 3 or 15 ohms. Response: 45-13,000 c.p.s. 
Bass resonance 40-50 c.p.s. Solid aluminium chassis. Brand new 
with 12 months unconditional guarantee. P. & P. 6/6. 

• BARGAIN— BAKER-SELHURST GUITAR GROUP 25 — 
£4.19.6 ONLY. 12in. dia. round, 25 watt rating, 12,000 lines gauss, 
15 ohms. Response: 30-10,000 c.p.s. Solid aluminium chassis. 
Heavy duty core. Brand new with 12 months unconditional guaran- 
tee. P. & P. 6/6. 

• CARTRIDGES — ALL AT BARGAIN PRICES. 

SO N OTO N E 9T A/ HC sapphire (stereo) ...£2 

SON0T0NE 9TA/HC diamond (stereo) £2 5 

SONOTONE 2T ceramic HC (mono) '. . . . £1 2 

ACOS GP91/3 HC (mono) .£1 o 

E.R.S.M.B, crystal (mono) £1 o 

E.R.S.M.B. ceramic (mono) £1 

E.R.S.M.B. ceramic (stereo) £1 5 

TC8H (mono) £i o n 

TC8M (mono) £1 q o 

CI stereo ( £2 2 

All cartridges are supplied with fixing brackets and screws at no 
extra cost. 

• BARGAIN— PHILIPS INTERCOM SYSTEM— OUR PRICE 
59/6 ONLY. Retail value £6.6.0. This equipment is ideal for baby 
alarm, office, home. Hundreds of uses. Absolutely brand new in 
handsome presentation case containing all leads, etc. 12 months 
unconditional guarantee. P. & P. 3/6, 

• BARGAIN— CAR RADIOS — OUR PRICE 9 GNS. Retail 
value 16 gns. Negative or positive earth (switched). Well known 
brand name. Fully transistorised, 12 volt, medium and long waves. 
Speaker and fitting kit supplied at no extra cost. 12 months un- 
conditional guarantee. P. & P. 7/6. 

• BARGAIN— CAR AERIALS. OUR PRICE 22/6, Retail value 
37/6. Wing mounting, heavy chrome plate, retractable. A snip. 
Buy while stocks last, 

• BARGAIN — CAR RADIO/PORTABLE — OUR PRICE 4£ 
GNS. ONLY. Retail value 7J gns. Single waveband (medium). 
Fully transistorised. A beautiful radio, the performance has to be 
heard to be believed. 12 months guarantee. P. & P. 4/6. 

Free with this Radio — suitable window mounting car aerial, 

• BARGAIN — SLIMLINE TV RECEIVERS IN MINT CON- 
DITION. 17in„ 19in„ 21 in. Checked complete and working but less 
I.F. strip. OUR PRICE £9.10.0 ONLY. I.F. strips supplied at 45/- if 
required. Fitting charge for I.F, strip £2.2.0 if requested, P. & P, 
TV Set 30/-. P. & P. I.F. strip 5/-. If purchased together 30/-. 
Personal collection advised, otherwise despatched at customers risk. 

• BARGAIN— DIODES — OUR PRICE £1 for 750. In 750 lots 
only. All assorted. 



Our high fidelity equipment is not advertised due to space limitations. In stock and on demonstration all famous names 

Leak, Wharfedale, Rogers, Rason, Thorens. Up to 15% discount against recommended retail prices. 



S B ELECTRONICS 



ATLAS HOUSE, CH0RLEY OLD 
BOLTON, LANCS. 



RD. 



Tel.: BOLTON 25881 



157 



^JSjB JSIj 313 




/..."EAGLE PRO-:..' ; 

TRANSISTORIZED U«;0 
PHONO PREAMPLIFIER 

MODULE 

■ .g-HJ&'-TOLT DC OPERA T)QN 





FSBSBa 



EAGLE'S new range of plug-In 
ail -transistor miniature modules. 
EM.1 Phono Pre-amplifier 
EM. 2 Tape Head Preamplifier 
EM.3 Microphone Pre-amplifier 
EM.4 Power Amplifier 
Each module is completely 
assembled and supplied with 
mounting socket to enable them 
to plug in and out of circuits. 
Visit your EAGLE dealer to 
inspect these new miniature 
modules . . . such good value at 
32/6d. each. 



FOR VERSATILITY 

RELIABILITY AND 

SOUND VALUE 

INSIST ON 



«^ e V 




Distributed by 
B. Adler & Sorts (Radio) Ltd. 
Coptic Street, London, W.C.I 



HOME RADIO (Mitcham) LTD.. Dept. PW, 187 London Road, Mitcham, Surrey, CR4 2YQ Phone : 01-648 3282 




II! ElitlllllC EeiPIKINIS CIHUKOE 



"« SETS THE STANDARD 



/u 



Used and 
f acclaimed by:- 

SCIENTISTS 
ENGINEERS 
TECHNICIANS 
TEACHERS & 
STUDENTS 



This edition of the Home Radio Cat- 
alogue is the result of ten years of care- 
ful selecting, compiling and indexing. 

It is the most comprehensive we have 
ever produced — it has 256 pages, over 
7,000 items and over 1,300 illustra- 
tions. With each catalogue we supply 
our unique Bargain List, Book Mark 
giving Electronic Abbreviations, an 
Order Form, an addressed envelope, 
and 5 Vouchers each worth 1/- when 
used as directed. All this for only 7/6 
plus 2/- post and packing. Send the 
coupon today, with your cheque or 
P.O. for 9/6. 



Of course no catalogue is ever really 
finalised. As soon as we have one 

edition of! the press, our researchers get 
busy finding out what is the latest In the 
world of Radio and Electronics — ready 
for the next printing. 



Please write Name 4 Address in block capitals 



NAME 

ADDRESS 



Home Radio (Mitcham) Ltd., Dept PW, 187 London Road, 
Mitcham. CR4 2YQ 



158 



S-DeC 



professional 
breadboard 



S-DeCs are a professional breadboard 
which are used in their thousands in 
industrial and Government research labora- 
tories and being used increasingly in 
educational establishments from degree 
level electronics courses to the teaching of 
electricity to primary school children. This 
breadboard is sold world wide, and over 
50% of current production is exported. 



The diagram shows the layout of the 
contacts on S-DeC. Each S-DeC 
contains two of these panels, per- 
mitting most electronic building 
blocks to be accommodated. DeCs 
may be joined using the keying 
method provided « 
to form a stable 
area of any size. * 
The connection 4 
points are on a fin. 1 
matrix. Compo- ! 
nents are simply 4 
pushed into the £ 
contacts and may f 
be withdrawn at 4 

Will. 31 32 33 34 35 



- 



Experiment and Project Guides: S.D.C. Products provide a series of experi- 
ment and project guides for educational users. These are available to the enthu- 
siast and full details can be supplied, either from 'Electroniques' (Edinburgh 
Way, Harlow, Essex) or the manufacturers, S.D.C. Products (Electronics) Ltd. 

Accessory Kits: With every S-DeC kit purchased there are included 
accessories. A control panel is supplied for mounting such things as potentio- 
meters, and this panel simply slots into the S-DeC base. Other accessories 
include small compression springs for making solderless connections to 
controls and clips for mounting such things as ferrite rods on the panel. Also 
included with each kit is an instruction leaflet and booklet of projects. 

Projects on S-DeC: In every kit a booklet of circuits is supplied with full 
instructions for assembly of the circuits on DeCs. The circuits include a three 
transistor reflex radio with diode detection, morse practice oscillator, 
electronic flasher, a monostable multivibrator, a three stage audio amplifier, 
(picture of amplifier mounted on a DeC below) and circuits for a number of 
oscillators. 



Insertion/Withdrawal 

Force, 90 gm.wt. 

Capacitance between 
adjacent rows of 

contacts 3pF. 

Resistance between 
adjacent contacts 10mO 
Resistance between 
adjacent rows of 
contacts 10 "'0 




Single DeCs: One S-DeC with Control Panel, Jig and 
Accessories for solderless connections to controls, etc., 
with booklet 'Projects on S-DeC giving construction details 
for a variety of circuits. 29/6d. retail. 



4-DeC Kit: Four S-DeCs with two Control Panels, Jigs 
and Accessories and the booklet 'Projects on S-DeC all 
contained in a strong attractive plastic case. Ideal for the 
professional user, £5.17.6d. retail. 



Available from leading suppliers and 'Electroniques' dealers 



in case of difficulty DeCs may he purchased direct from the manufacturers. Include 6d. (in the case 
of single DeCs) and 2f6d. (in the case of 4- DeCs) to cover postage and packing. 

S.D.C. PRODUCTS (Electronics) LTD 

Corn Exchange : Chelmsford : Essex 

TELEPHONE OCH 5 56215 



159 



VALVES/SEMI-CONDUCTORS 

BRAND NEW & GUARANTEED 



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El TK2 


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F.CIMii 


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ECU 42 


11/- 


j.-; ■ ■ j i ~ t 


8/3 


BCBSS 


8/6 


]■,'■ 1 90 


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7/- 


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ECL80 


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«/- 


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b/- 


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EL91 


4/- 


EI.95 


5/3 


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7/6 


EM81 


8/- 


EM84 


7/6 


EM83 


7/8 


EY51 


7/6 


EYM 


if- 


F,/l" 


8/6 


KX41 


s/ a 


Ezsn 


5/e 


EZ81 


5/8 



G?,32 


11/6 


OZ34 


11/6 


sn*i4 


8/- 


PAFC> 


>7/6 


PCCS4 


8/6 


POOSS 


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pocas 


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FCOS9 


11/6 


PCO 189 18/8 


pass 


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s/a 


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p< ■].-•:; 


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»/- 


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10/6 


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7/8 


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8/- 
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8/- 
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L"25 
C36 

U1B1 
U281 

use i 

TT801 

UABC808/- 
UAF42 10/- 
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UBF89 II- 
OOCS4 10/- 
OOC8S 7/ 
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VHH42 10/- 
UCH81 7/- 
OCL89 8/- 
LCL83 10/- 
L:F41 10/- 
IT80 
UF-S 
1T-9 
UL41 
t."E84 
OY41 
TYSm 



7/- 
7/6 
7/6 
10/- 
II- 
7/6 

a/e 

YE 105 ,'30 

s/e 

Yni50,'3r> 
5/- 

B1ANY 

OTHER 
TYPES IS 
STOCK, 



TRANSISTORS 



2K 753 4/8 


BCI08 5/6 


OC71 


4/- 


ST140 4/- 


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(ic;m 


5/- 


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2X 2928 5/- 


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OC74 


b/6 


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AC107 4/6 


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oc,r» 


4/6 


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4/6 


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PHOTO- 


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(JET873 5/8 


i )« :s 1 


n- 


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(K :x I M 


am 


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AD140 8/6 


MAT100 7/9 


0081 D 


ti- 




AD149 16/- 


HEATlOlS/e 


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SIGNAL 


.\ DT140 


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(1C--.' 


ns 


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OAZ20012/- 
OAZ20110/- 
OAZ202 8/6 
OAZ203 8/6 



ZENER DIODES 

OAZ204 8/8 



O A 55205 8/6 
OAZ206 8/8 
OAZ207 9/8 



OAZ208 6/6 
OAZ209 6/6 
OAZ210 6/6 
OAZ211 8/6 



OAZ212 6/6 
OAZ213 6/6 
OAZ227 15/- 



STC. 1 WATT SERIES 5% 

2.4 2,r s:>.-> 4.:; is to 1? in sn :>.;. rolt, 5/- emM. 
Z series. All voJlages from 3.9- SO volt. 250 nilV, 8/6 ea. 

1.5 w. 4/- ea. 7 ft. 61- each. 



SILICON 


POWER DIODES 


60 P.I.V. 


•5 AMI' 6/li 


290 MA 


4001M.V. 


2/- 


samp 7/a 


70P.I.V. 


700 P.I.V. 


I AMI' 3/6 


100 AMP 


140 P.I.V. 


39/- 


166MA 1/- 


800 P.I.V. 


150 P.T.V. 


aooMA 5/6 


25 AM P10/- 


800 P.I.V. 


200 P.I.V 


3 AMP 7/6 


6 AMP 5/6 


iooo p.i.v. 


400 P.I.V. 


6 AMP 7/8 


500MA 3/8 


1000 P.I.V. 


400 P.I.V. 


650MA 8/8 


THYRISTORS 


SILICON CONTROL 


RECTIFIERS 


400 P.I.V. 


200 P.I.V. 


3 AMP 7:0 


7 AMP1S/6 


ioo p.i.v. 


400 P.I.V, 


7 AMF13/6 


7 AMP 15/8 


PLEASE 


ADD 


POS - 


fAGE 



LAFAYETTE TE46 RESISTANCE 
CAPACITY ANALYSER 



2 pF-2,000 DlFtl 
2 ohms 200 mfig- 
ahms.AUo checks 
hapedanee, i nn, ■ 
ratio, insulation, 
20(1. 250V A.C. 



Brand New £16. 
Carr.7/6. 




T.E.40 HIGH 

SENSITIVITY AC 

VOLTMETER 

10 meg. input 10 ranges : 
•0l/'0O3[-i;-3/l/3/10 / 30 
;100'300V. B.M.8.4cps.- 
t-2MC;9. Decibelt -40 to 
1-60 dB. Supplied brand 
tiaw complete with leads 
and toBtruetloiia* Opera- 
Hon 230V. A.O. 817.10.0. 
Cftrr. 6/-. 




T.IM.C. 1000 SERIES 
KEY SWITCHES 



1 why, 2 c/o 7/6; 1 w»y, 2 c/o 2b, 7/6; 1 way 
4 a/o, 8/-; 2 way, 3m., 3 m. 8/6; 2 way, 2 c/o, 

2 v o, 8/6; 2 way, 8 c/o, 4 eh, 10/-. 
p. i*t extra. Quantities available. 




ARF-100 COMBINED AF-RF 
SIGNAL GENERATOR 




,|i.i;'t] 



'.VLiV 



M 



30.000 c/8. O/P 
HIGH IMP, 21V 
P/1'600 n S-8V P/l*. 
TF lOOKc/a-300 
Mc/s. Variaiilf H.F. 
att^nnalion inl.'e^t. mCKluiat ion . Incorpor- 
atea dual purpose meter to monitor AF out- 
put Md % mod. on R.F. 220 240V A.C. 
£27.10.0. Carr. 7 6. 



TE-20RF SIGNAL GENERATOR 

Accurate wide range Hlgtial generator covor* 
ing 120 Ko/s— 260 
Mc/s on 6 tiaucts. 
DirtfLtfr- canijralt'il 
Variable E.E. at- 
tenuator. Operation 
200 (2 40 Y. A.C, 
Braud new with In- 
structions. J15.0.0. 
P. * P. 7/6, 8.A.E. 
lor details. 




AUTO TRANSFORMERS 

0,'llo/280Y. Step up or «tep down, Euilj- 
shrouded, 

600 W. £3.10.0 P. .V I'. 0'(i. 
1,000 W, £5.10.0 P. 4 P. 7/fi, 
1,500 W. £6.10.0 P. 4 P. R.'fi. 
3,000 V. £7.10.0 P. * P. 12/6. 
7,500 W, £15.10.0 P. * P. 20/-, 




ADMIRALTY B.40 RECEIVERS 

Just released by the Ministry. High auality 10 valve receiver 
manulactured by Murphy. Coverage in 5 bands 650 Ke/s-30 Me/s. 
l.F. 500 Kc/s. Incorporates 2 E,F. and 3 I.F. «Uge«. Iiand- 
pasi filter, noise limiter, crystal controlled B.F.O., calibrator. 

I/F. output, etc. Built -in sneaki::. i>iil i i; 1 ■■ ;i - ■i-t" !I '■•■"• 

150/230 volt A.C. 8Ue I9J x 131 x 161(1, Weight 114 H». Offered 
in good working condition. £28.10.0. Oarr. 30/-, With cireolfc 
diagrams. Also available B.41 I„F. version of above. 15 Kc(s- 
700 Kc/s.. £17.10.0. Carr. 30/-. 



SOLATRONCD711S.2. DOUBLE 
BEAM OSCILLOSCOPE 

An extremely high 
quality oscilloscope 

originally costing £400. 
Switched beam. Iden- 
tical VI. V2 Amplifiers 
D.C. to 9 Mc/s. Sensi- 
tivity amV/CM to 100 
VICM. Time base 10tt/ 
*ec. to 10 M/secs. Call- 
bratoi', X amplifier D,G, 
to 2-5 Mc/s. Vi Modula- 
tion. 110/2O0/2J5OV. A.C. 
Supplied in good working order, £65, carriage 
£2, or available as received (mm Ministry un- 
serviced. £50. Carriage £2, (HandlmHiks £8 
extra,) 




AVO CT.38 ELECTRONIC 
MULTIMETERS 

High qualltv 97 range instrument which 
measures A.C. and D.C. Voltage. Current, 
Resistance and Power nidpnt. Ranges 
D.C. volts 250mV-10,000 v. (10 mcgQ- 
HOmgO input), D.C. current !0|iA 25 
amps. Ohms: n- 1,000 niegR. A.C. volt 
100 mV-250V. (with R.F. measuring 
lieitd up to 250 Me/s). A.C. current 10&AA- 
25 amps. Pivwf "iitput 50 ruiijrn-watts-B 
watts. Operation 0,,'110;200,'230v. C. 
Supplied in perfect condition complete 
with circuit lead and li.F. pn>be £25. 
Carr. 15 -, 



MARCONI TEST EQUIPMENT 

Es-Milltarr reconditioned. T.F. 144G Standard Sig- 
nal Generators. 85 Kes-25 Mc's, £25. Cirr. 30,'-. 
T.P. 885 Video Oscillator. 0-5 Mc;s. £45. C*rr. 3fi -. 
T.F. 1B5M. Beat Fre(iuenoy OsciDator. -10 Ke/s, 
200/250 v. A.C. £20. Carr, 30/.. All above u tiered in 
excellent condition fullv tested and checked. 
T.F. 1100 Valve Voltmeter, Brand new, £50. T.F. 1267 
Transmission Test Set. Brand new, £75. 




AM/FM SIGNAL GENERATORS 

OaciHator Test .\o. 
2. A high quality 
precision instru- 
ment made lor the 
ministry by Airmeo. 
Frequency cover- 
age 20-80 Me/s. AM/ 
CW./FM. Incor- 
porates precision dial, level meter, precision 
attenuator 1 (xV-100mV. Operation from 12 
volt, D.C. or 0/110/200/250 volt A.C. Size 
12 x Six Sin. Supplied in brand new con- 
dition complete with all connectors fully 
tested. £45. Carr. 20/-. 




TYPE 13A DOUBLE BEAM 
OSCILLOSCOPES 

An exceUenl general 
purpose D/B oscillos- 
cope. T.B. 2epa-750 
Kc/s. Band with 5-5 
.Me/s, Sensitivity 33MV/ 
CM. Operating voltage 
110/200/250V. A.C. 
Supplied in excellent 
working eo mttttwi . 

£22.10.0. Or complete 
with all accessories, 
probe, leads, ltd, etc, 
£25. Carriage 30/-. 




Varidfe foftaoe TRANSFORMERS c 



Brand new, guaranteed and rivci-iage paid. 

itieb. ,',n:Uu i- i-..n<tru<:lMIl. ilipul. 230V. :i0-r>() u.i'rlcs. 

Output full 'variable from 0-200 volts. Bulk nuiHitities svailsbta 
1 amp.— £6.10.0; 2-5 amp.— £6.15.0; 5 amp,— £9.15.0; 
8 amp.— £14.10.0; 10 amp.— £18.10.0; 12 amp. — £21.0.0; 
20 amp.— «37v0.0. 





PRINTED 
CIRCUITS 

Five assorted 
printed circuit 
boards with 
transistors, diodes, 
resistors, conden- 
*wr*, etc. Guaran- 
teed minimu m 
20 transistors. 
Ideal for expcrl- 
loenlers. 5 boards 
for 10/-. P. & P. 
2/-. 



TE22 SINE SQUARE WAVE 
AUDIO GENERATORS 

9!ae: 20e/s to 
200 Kc/s on 4 
bands. Square: 
20c/e to SOKc/s. 
Output imped- 
ance 5,000 ohms, 
200 /250 V A.C. 
Supplied brand 
and new guaran- 
teed with instruc- 
tion manual and leads, £15. Carr. i/G. 




DUB1LIER NITROGEL 
CONDENSERS 

Brand new. 8 mfd. 800V. 8/6. P. & I 
2 niFd. 5,000 V., 42/6. P. & P, 5/-. 



LUCAS 20/0/20 AMMETERS 

Brand new boxed. Suitable car-motorcvcle. 
12/6. P. * P. 2/-. 



LELAND MODEL 27 BEAT 
FREQUENCY OSCILLATORS 

O-aa^Kc'i. Output 5K or 500 "Inns. 200/250 
V. "A.C. nffered in excellent condition. 
£12.10.0. Carriage 10/-, 




AVO METERS 

Supplied in excel- 
lent condition, 
fully tested and 
ehecked. Comp- 
lete with prods, 
leads and inst- 
ructions. 

Model 47A 
£9.19,6. 

Model 7 £13.10.0 
Model 8 £18, 

P- Jt P, 7/6 each. 



SOLARTRON MONITOR 
OSCILLOSCOPE TYPE 101 

An extremely high quality nsdlloscupe 
with time base «t lOQ/sec. lo 20 m/see- 
Interaat Y amplifier. Separate mains 
power supply 20 250 V. Supplied in 
excellent condition with cable*, prohe, 
etc., as received from Ministry. £8.19.6. 
Carriage 30/-. 



R.C.A. AR88 SPEAKERS 

Bin. 3 ohm speakers in metal case. Black 
crackle finish to match our 88 Iteceivers. 
Available brand new and boxed with leads. 
58/6. Carr. 7/6. 



HANSEN SWR BRIDGES 
52 ohm 69/6 P. & P, 8/8 




160 



MULTIMETERS for EVERY purpose! 



MODEL AS -1 ODD. IMS" 
VOLT Sin., mirror sealr. 
Bnilt-in mi'li-r protect ion. 
/ 3 / 12 ■ fill / 120 / 300 / 

600 / i,aoo v. dc. o ,'6 ; 30; 

320/300/600 v. A.C. 0/ 
30uA I « / 60 / 300HA I 
12 Amp. 0/2K J 20 OK / 2M / 
200MJ). —20 to +17 dB. 
£12.10.0. P. a P. 3/6. 





MODEL TE-I6A. 200kfl/ 
Volt 5/25,50; 250 500 2.500 v. 
DC. 1Q/5Q;100/500/1,000 v. 

O.ooVaj'2-6 m A/250 mA D.C. 

t SK/6 meg, ohm. — 20 to 

+23dB. 

1O-0, 300 mFd.O' 100-0,3 mFd. 

69/6. P. it P. a/6. 



MODEL TE-70. 30,000 
O.P.V. 0.» l5'GO'3OO"600 
,•1,2011 v. Hi- (I .:'3o 120, 
600/1.200 v. A.C. 0.30 [LA 

IS/JHITtllOmA H'lliKi'lHO 

K/i-iiM/m Meg. a. 

£5.10,0. P. * P. 3/-. 





— ^^ NEW MODEL BOO 30,000 

ky"^r=-0 OJ,V. with overload 
H l^-rTOI Srotection, mirror scale 

I ->\ J 230/800/1.000 V Ij.ro 2 5 
1 ft _\jJjW 10 25 100 I 230 ,' 800 J 

I KEraQ < .oon v. a ,c. o 'sofiA/s.-so: 
liMWH 5lJ,J mA - '-' iim i' DC - 

^CTRflf O'OO K'i. Meg./fiO. Meg. a. 
Xj5fiW»** £8,37.6. Post paid. 
MODEL TE-1S 20,000 OPV 
,' •<> / 6 / 30 / 120 / 600 / 1 ,20 i 
3,000/6,000 V. D.C. 0/6/30,' 
320/600/1.200 V. A.C. 

0/6 Li A / 6 / 60 . 600mA . 0/6 / K 
.'dOOK'OMeg. 60. Meg. fi50 
pF. 0'2 mFd. £5.19.0. 
P. & P. 3/6. 



MODEL TE.SO. 20,000 
O.P.V. 

0/10/50/ 100/BOO/l.OOO v, 
A.C. 0''5 l 2fl/50. , 250,'500i' 

1,000 v. D.C. 0-50 DA, 5/ 
SOfoOOniA, r 6K760K;60OI£ 
/6 meg, £4.17.6. P.P. 3,'-. 





TE-S1, NEW 20,0000/ 
VOLT MULTIMETEB. with 
overload protection arid 
mirror scale. 0/6/60/ 120, 
1,200 v. A.C. 0/3/30/60/300/ 
6 00 IS.OOOv. D.C,0 J 'B0(i>./12 
/300mA. D.C. SOKifl meg. 
ohm. 86/-. P- * P- 2/6. 



MODEL 2oQJ. 2,000 
OJ.V. 0/10,50-500 

2,500 V. D.C, 0/10/50/ 
50O;2,o00 v. A.C. 0/2 
Meg. O. 0/250 mA. 
—20 to + 36 dB. 
4B/6. P. * P 2/6 





MODEL PT-34, 1.000 
O.P.V, 0/10(50/250/ 
500/1,000 t, A.C. and 
D.C. 0/1/100/600 mA, 
D.C. 0/100 KC 39/8, 
P. A- P, 1/6. 



LAFAYETTE 57 Ban go 
Super 50St(!/volt Multi- 
meter. DC, volts 125mV 
-1000V. A.C. volts 1-5V 
-1000 V. D.C. current 
25 n A- 10 amp. Ohms 0- 
10 Tiutgtl. tlB —20 to 
+ 81dB. Overload pro- 
tectiou. £12.10.0. Carr. 
8/8, 




MODEL AP-105. 50k 0/ 
Volt. .Mirror scale, built. in 
meter protection. 0/-3/3/12/ 
60; 120/300/6OOJ ■ J,2uflv. D.C. 
■i>/l,200 v. 
A.C. 0/30 u. A/6 ,'60/ 300mA/ 
12 Amp. 0/10K/1M/10M/ 
100 Mil. —20 to +17 dB, 
£3.10.0, P. & P. 3/6. 




MODEL ZQM TBANSISTOR 
3t has the fullest opacity fo; 
chewing "II A, B and Icn 
Ei|iinlly adaptable for check, 
ing diodes , e Ic . Spec : A : -7- 
0-9907. B: 5-200. Ico: 0-50 
microamps 0-5mA. Beats - 
tauce lor diode 200 SJ-3M jj . 
Supplied complete with in- 
Effractions, batterv and 
lea.!*. £5,19.6. P. £ P. a/0. 




TE-65 VALVE VOLTMETER 



High Quality instrument 
with 29 ranges. D.C. volts 
1-5-1,500 V. A.C. ToMa D5- 
1,500 v, KesUtance up to 
1,000 megohms, 220/240 v. 
A.C. operation. Complete 
with probe and Instructions 
£17.10.0. F, & P. 6/-. 
Additional Probes avail- 
able: R.F. 35/-. H.V. 42/6. 




H0SIDEN DHFJ4S2.WAY 
STEREO HEADPHONES 

Each headphone contains 
a 2 Sin, woofer and a $fn. 
tweeter. Built in indivi- 
dual level controls. 25- 
33,000 c.p.s. SO imp. 
with cabin and stereo 
plug, 
£5,19.6. P. & F. 2,'8. 




F.M. WIRELESS 
MICROPHONES 

94-104Mc/s, Transistor- 
ised, Operate from OV 
battery. Complete with 
additional secret tie-clip 
mierophunc.LJ^t £ 12, 1 0,0 , 
ONLY £6,15.0. P. & P. 




TRANSISTORISED 
TWO-WAY 
TELEPHONE 
INTERCOM 

Operative over ayuazingh- 
tong distances, Separate call 
and press to talk buttons, 
2- wire connection. 1000 T s of 
applicatlona. "Beautifully Sn- 
lelied in ebony* Supplied 
enmplcte with batteries ajirf 
wall brackets, 
£6.19.6. P. & F, S/&. 



GARRARD DECKS 

Brand N'ew and Guaranteed. 

102S with cartridge £7.10.0 

A70 Mk II less cartridge £12.13.0 

LAB 80 Mk II less cartridge £23.10,0 

LAB 80 Mk n with base £27.10.0 

401 Transcription less cartridge £27.0.0 

Carriage 7/6, 



t ! 



2-WAY RADIOS 



Super quality]. Brand new 
- ^M and guaranteed. 

3 transistor £6.1 5 . pr, 

4 tranaistor £6.18.6 pr, 

5 transistor £7,19.6 pr, 

6 trans Istor £8.12.8 pr. 
6 tra-L-dstor Dc Luxe 

£32,10.0 pr. 
10 transi si , ir £28. 10.0 pr. 
13 transistor 600 mW £31,10.0 pr. 
Post extra. These cannot be operated in U.JC. 




SINCLAIR EQUIPMENT 

Z12 12 watt amplifier. 89/6 

PZ4 Power Supply Unit 89/8 

Stereo 26 I' re am p., £9.19.6 

Q14 Speakers, £7.19.6 

Micro malic Radio Kit, 

49/6. Built 59/6 

Micro PM Badio Kit 

£5.19.6 

ALT- POST PAID 

SPECIAL OFFER 
2 Z18 Amps., FZ4 Power Supply. Stereo 
25 Preamplifier, £22, or with two Q14 
speakers £37, 




CLEAR PLASTIC PANEL METERS 

First p-ade quality Moving Coi I panel metersavallable ex-*tock, 
S.A.E. for Illustrated leaflet. Discounts tor quantity. Type 
MB 38P, 1 . , in. square fronts. 

AtaA 35/- 

100mA 25/- 

350mA 26/- 



.37/6 



50ttA 

50-ft-GOLtA 35/ 

100 aA 36/- 

100-0-lOOrjui 32/6 5amp 88/- 

200(jrA 32/6 20mA 25/- 



;n!ii-ri-500'j.A25/- 

ImA 25/- 

1-0-lmA 25/- 

2mA 26/- 

5mA 25/- 

10mA 25/- 

750mA 26/- 

3 amp 25/- 

2 amp 25/- 



200mA 
300mA . . . 
500mA . . . 
3V, D.C. . 
10V". D C. . 
20V. D.C. . 
50V. D.C, . 
100V. D.C. 



600|aA. 



.25/- 
.26/- 
.25/- 
26/- 

. 2ii - 

, 26/- 

25/- 

.26/- 



350V. D.C. .96/- 
300V. D.C. .26/- 
500V. D.C. .26/- 
750V, D.C. ,25/- 
15V. AC. . .26/- 
50V. A.C. . .25/- 
160V. AC. .85/- 
300V. A.C. .25/- 
500V. A.C. .86/- 
3 meter 1mA 89/ B 
VU meter ..38/9 



37/9 Post Estra. 3-argcr sizes available — send lor lista. 



UNR-30. 4- BAND 
COMMUNICATION RECEIVER 

Covering 550 Kc/»-80 Me/s. Incorporates variable 
Bl-'O for CVi'/SSB reecptlon. Built in speaker and phone 
ia.-k. Metal cabinet. (J)KT.-iti<.ii d20,- , -j4i> V . A (' Sn(i t ;ied 
brand new, guaranteed with instruc- f 12 1(1 D 



ri.,ri'i. 



Carr. 7;6. 




LAFAYETTE MODEL HA-700 AM/CW/SSB AMATEUR 
COMMUNICATION RECEIVER 

8 Valve* , 5 bands incorporating 2 MBCHAN'ICAL 
iULTEES for exceptional selectivity and sensi- 
tivity. Frequency coverage on 5 bands 150-400 
Ke/s, BSOA.WW Ke ; s, 1-lH'oMc/s, 4-8-14-5 Mc/s, 
10-5-30 Mc/s, Circuit Incorporates E.F, stage, 
aerial trimmer, noise limller, B.F.O. product 
detector, electrical bandspread, 9 meter, slide 
rule dial. Output lor phones, low to 2k Q "r 
speaker 4 or So. Operation 220/240V A.C. Size 
7 i ■ I i"i -. lOin. Supplied brand newandguaraiit,-rrd 
with haudlKiok. 36 GN8. Carr, 10/-. S.A.E. lor leaflet. 




LAFAYETTE MODEL HA-500 SSB/AM/CW 80 THROUGH 6 
METRE RECEIVER 

New outstanding Hani I$NMfc9 qtilv receiver covering 
iSm- ^^.^O.'SC'lo.ao.fi mvtrc bands. Incorporates 10 
ralvcs, product detector, two mechanical flttarn, 8 
Meter, dual conTersion on all bands, crystal calibra- 
tor. B.F.O. noise 11m i tc r, ne rial t rimmer* I - F.a* 2, 6 OS 
Mc/s and 455 Ke/sf. Output 8 ohms and 500 ohms. 
Operations 220, ,+ 2-40 yolta A.C. Supplied brand new 
and guaranteed with handbook 42 dna, C&rr 10/-. 
100 Ec/a. crystal, 35/-, 









^ liSsssssSrfiftl 




- W ® ^@ : '9 ® ^ a0 1 



LAFAYETTE LA-224T TRANSISTOR STEREO AMPLIFIER 

10 IraiiHlstors, 8 dii>,les, IHF music power, 30W 
at 80. Response 30-^0,000 ±2dB at 1W, Dis- 
tortion I '„ or Its.-. Inputs 3mV and 2J"iuV 
Output 3-30 O. Separate t.. and B. volume con- 
trols. Treble and bass control. Stereo phone lack. 
Brn.ihed aluminium, gold anodiged extruded front 
panel with complementary metal case, Size 10 1 x 
3 0/16x7 13,'16in. Operation 11S/230Y A.V. 
JE2S. Carr. 7/8. 




* TRANSISTORISED FN! TUNER * 

TBAySIPTOFi 
HIGH QUALITY 
USEE, S 3 7, H 
O^I^Y 6x4x21 In. 
•J l.F stages, 
jg Double tuned dis- 
criminator. Ample 
output, to feed most 
amp 3 if: e r* . U p i.' ra I, ■ -, 
Coverage flS-lOSMc/s. 

Beady huilt ready for use. Fantastic value 

for money. £6.7.6. P. 4 F. 2/6. 

Stereo mnltinex adaptor* 5 gus. 




TRIO COMMUNICATION 
RECEIVER MODEL 9R-59DE 



on 0V battery. 



AMERICAN TAPE 

First grade quality American tapes. 
Brand new. Discount on Quantities, 

Uln., 228ft. 3,.P. acetate .3/6 

Siln. 600ft. T.P. mylar 10/- 

oin. 600ft. atd. plastic 8/6 

Sin, 800ft. LP. acetate 10/- 

6ln. 3,200ft. D.P. mylar 15/- 

Bln. 1,800ft. T.P. mvlar 88/8 

Otin. 1,200ft. 1..P. acetate 18/8 

ojln, 3,200ft. L.P. mvlar 18/- 

Oito 3,800ft. D.P. mylar 88/8 

OJln. 2,400ft. T.P. mylar 39/8 

7lm 1,200ft. atd. acetate 12/8 

7ln. 3,800ft. L.P. acetate 15/- 

7in. 3,S00ft. mylar 80/- 

7in. 2,400ft. D.P. mylar 85/- 

7its. 3,600ft. T.P. mylar. , 46/- 

Postage 2/-. Over £3 post paid. 



COSSOR DOUBLE BEAM 
OSCILLOSCOPES 

TYPE 1035 ficneral purpose A.C. coupled. 
TYPE 1049 L.F., D.C. coupled, £36 each, 
Carr. 30/-. 



L: 






■© 



-! 



4 band t'-.i-iv.-r ,■ v.Tiiitf 55f, Kr - !,. 3( 
Mes. e^ulrliiioii-, .•mi elect ru-al run id- 
spread on 10, 15, 20, 40 and 80 metres, 

5 valve plus 7 diode circuit. 4/8 ohm 

-.i.i:--.i.|f ii-..: Hi - : ;i. k oSB-C\v • ',M, 

• Variable BFO • S meter. • Sep. band 
spread dial. • IF 456 Kc/s. • Audio 
output 3-5 W, • Variable BF and AF 
gain controls. 11 5/250 V, A.C- Mains 
Beautifully designed. Size: 7 x 15x10m. 
With instruction manual and service 
data £37.10.0. Carriage 12/6. 



MAGNAVOX 363 3-SPEED 
TAPE DECKS 

4-track, £13,10.0. Carriage extra. 



RECORDING HEADS 

Renter i-track. As fitted to Cotlaro Mk. IV 
and Studio Decks. High imp. record play 
back, low imp. erase. Brand new. 39/8 
pair. Miniflnx 4 track, set ol 3 88/6, 
Cosmocord with mounting plate: 

Til 1-5CU1; P..TV m Mini. 'replay 66/, 

3'iU-l'>lVi'.'lV r i- ,: i. r,,l/ replay 65/- 

TKLl-eP/W erase 80/- 

I'ost extra. 




(RADIO) LIMITED 

r Phone: GERHARD 8204/9155. 

s^-^T. Cables: 5MITHEX LESQUARE 

3-34 LISLE STREET, LONDON, W.C.2 




161 




960 
PAGES 

THE COMPLETELY 
NEW 1968 ELECTRONIQUES 

MANUAL 
12 HOBBIES SECTIONS PLUS 
OVER 12,000 COMPONENTS 

AND SPECIAL VOUCHER 
OFFERS COULD SAVE YOU 
£25 IF YOU BUY THE MANUAL 
NOW! 




The 1968 Hobbies \^*=***~~~ Manual now contains 
KNIGBTKITS— a famous American range of 

electronic easy-to -build kits. HALLICRAFTERS — the 
N umber One name in communication equipment and radios. 
BOOKS— over 140 titles. AUDIO and HI-FI— a, wide, wide 
range including famous names like Goodman. Sinclair, 
Sonotone, Acos, Discatron, etc., etc. HOME AND HOBBY— 
something for even- member of the family — microscopes, 
telescopes, radio controlled equipment, garage door openers, 
experimental and educational kits. etc. MOTORING— & 
special section with money-saving engine tuning kits, 
radios, seat belts, a car vacuum cleaner and many other 
useful accessories. SHORT WAVE LISTENING— exciting kits 
and finished equipment for world-wide reception. TEST 
EQUIPMENT AND TOOLS— a. very wide range including 
multimeters, oscilloscopes, signal generators, soldering 
irons, cutters, pliers, breadboarding kits, etc., etc. 
COMPONENTS— over 12,000 items from more than 100 
manufacturers. The most comprehensive range available 
from a single source — now bigger than ever before, 
AMATEUR RADIO— the best of receivers, transceivers, aerial 
rotators, aerials . Qoilpax modules and lots more. 
ELECTRONIQUES PRODUCTS— boxes and assembly systems, 
transistor and valve Hamband and General Coverage 
tuners, crystal filter I. F. amplifiers, oscillators and other 
modules for effortless high performance. And finally 
SEMICONDUCTORS AND VALVES— a new section of famous 
brand names like STC, RCA Newmarket and Brirnar, 



Enclosed is a che que /postal order for 1616 (which includes the 
5/- pp) made payable to Klectronlques fProp. STC) Ltd. Please 
rush me my 960 -pa;? e copy of the new 1968 Hobbles Manual. 



I PW/1 

I Send this coupon quoting the special limited- period offer to : 
, Electroniques (Prop. STC) Ltd. , Edinburgh Way, Harlow. Essex ' 



I 




electroniques 




LONDON'S LOWEST PRICES! 



Valves 




1A7 


9/6 


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10/6 


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7/6 


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1D5 


9/- 


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6/6 


1F2 


5/6 


1FP1 


7/9 


1G4 


10/- 


1HS 


8/6 


IT. AH 


8/- 


1LH4 


»/- 


1M3 


9/6 


1VUT 


8/- 


1X25 


18/6 


IN 3* t 


6/- 


1X72 


6/- 


lXiSfiO 


4/6 


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8/6 


1E5 


6/6 


1S4 


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ITS 


7/6 


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7/- 


2A7 


10/ 


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seal 


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2D2 


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12/0 


3 A3 


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9/6 


334 


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4LD4 


13/- 


5A 


10/6 


5AS4 


7/6 


ST4 


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5V4 


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5Y4 


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01. 


14/- 


6AB4 


8/- 


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6AF6 


13/6 


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6/6 


6AK6 


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6AL3 


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fi A MS 


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6BJ5 


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6BM8 


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BOB 


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6C10 


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BC31 


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tern 


6/6 


GCE8 


9/6 


6CJ5 


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6CK.6 


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GCM5 


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61- 


i3CU6 


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(30 W4 


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GOY3 


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fii)3 


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ens 


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SF19 


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GF22 


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6F26 


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6F30 


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6FG6 


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BOG 


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6GV8 


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6HG 


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GHU8 


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6J6 


5/6 


B.TX8 


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6K7 


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6K23 


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6E8 


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61.16 


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6LD3 10/6 
BM>20 71- 
GNU 8/- 



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GPlo 
0O4 
6E7 

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(3SI37 

GSK7 

BB07 

(SHT7 

SU5 

HV4 

6X2 

0Y6 

7A4 

"A7 

7A07 

7B5 

7B8 

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71)5 

7BJS 

7K7 

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TII7 

7K7 



13/ 
5/6 

30/- 
8/- 

12/- 
71- 
8/- 
8/- 
9/6 
8/- 

10/- 
6/6 
9/6 

13/6 

10/- 
8/- 

18/- 

10/- 
8/6 
8/- 
14/- 
13/- 
11/6 
8/- 
12/- 
14/- 
8/- 
8/6 
17/6 
12/6 
9/6 
9/8 
9/6 
11/- 
9/6 
9/- 



H I 15 

9A8 

9AQS 

91)4 

9C8 

10F1 

10F18 

10L14 

WED13 9/8 

IOPI4 18/- 

1-2AB 18/- 

IdACS 10/6 

WAFjG 9/6 

tsAxa 9/- 

1'2AT7 6/6 

I'JAVB 7/6 

1JAVV7 22/6 

l-.'BAB 8/- 

12BL« 10/- 

].> DT7 g^ e 

iaFB5 18/6 

12J7 9/- 

12K7 9/- 

1'2S7 11/- 

128Fi5 11/- 

12SH7 7/ 
1291,^ 



9/6 

128K7 7/- 

12SY7 8/- 

l'-'Y4 4/6 

)3 OS 7/- 

tSGC3 18/6 

14KB 8/- 
14L7 
1487 

I .HI 

Ijli 
1GY9 

I7Z3A 7/6 

16TJB 7/6 

ISIiXG 10/6 

.']>(.- 9/- 

19(3 B 17/6 



9/6 
17/0 
12/- 
10/- 
16/6 



ItlflU 
19Y3 
20PI 
201" S 

aiiis 

■S:< 05 



T,' 6 
7,'S 

14/ 

21/B 

ate 

121- 



25FGG 15/ 
■25 Y5 18/- 
aSZB 13/- 
2SAK8 8/6 
30A5 9/- 
30C15 15/- 
30FB 13/6 
30FL13 12/6 
30L15 14/6 
30P12 15/- 
301*19 15/- 
30PL1415/ 
33 A3 11/ 



3505 
35 W 4 
35Z5 
41A 
■l-JMT 

■i;.m: 



8/6 

e;6 
s/s 
s;- 

9/6 
8/6 



50BM8 10/6 
50L6 10/6 
54 KU 12/8 
B2TH 11/- 
63TP 8/8 
fiSME 9/6 



84 


7/- 


141 DDT 9/8 


150B2 


13/- 


177 


6/- 


277 


8/- 


409A 


12/6 


879 


6/- 


1221 


6/6 


1274 


10/6 


1638 


3/6 


1853 


0/6 


'3101 


10/6 


6488 


7/- 


88803 


12/6 


A405I 


12/6 


A C2 


9/8 


AC. 5211 9/6 


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9/6 


A 04 


8/6 


AZ11 


10/- 


AZ41 


e/e 


B63 


6/8 


B152 


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B339 


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B719 


8/0 


BF62 


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DAF9t 


7/9 


DF92 


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DU77 


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DHll> 


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DH147 


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DH718 10/- 


DK92 


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HI. :il 


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D1.94 


8/6 


DM13 13/6 


EABC80 8/6 


EP.34 


2/6 


EBC41 


10/6 


EBCBt 


71- 


SBPSt 


8/6 


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1S/- 


j;ccs:( 


8/8 


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8/6 


El -i : 1 vi 14/- 


ECV80 


9/6 


KOFS'i 


18/6 


l-OH-l 


8/6 


Baun 


8/6 


ECTA1 


13/6 


EF37A 10/8 


EF41 


11/6 


F,l-'-;; 


12/6 


EF8U 


7/6 


EFD5 


7/6 


EI. 1(3 


12/6 


EU38 


27/6 


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8/- 


ELI.SO 


17/- 


EM 80 


8/6 


BHBfl 


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EY88 


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V.'iW 


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6/6 


ni!i;:n 


0/6 


H02 


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HP8 


8/- 


KT01 


20/ 


Kl>» 


27/6 


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10/6 


L^3l^ 


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8/- 


N77 


5/8 


M42 


10/6 


J7147 


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N154 


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N309 


6/- 


N379 


8/6 


N727 


S/- 


PC86 


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l'0«8 


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]•'■; 


14/- 


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rf:oss 


9/6 


PI ... -*4 


14/- 


1*1 ■(■-(' 


14/6 


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PCCS0514/6 


l'CCS0616/- 


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12,/ IS 


PCF82 


9/6 


3'OKXI 


10/6 


l'OFHfi 


11/- 


PCF87 


15/- 


frl'siirns; 


i"'KMH12/(j 


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Pi.-K.-it.-. 12;6 


PCF806 15/- 



POPS 08 16/- 
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PCL83 10/- 
PCL34 10/- 
PCL85 11/6 
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PCLS0016/- 
PCL80116/- 
l'FL20016/6 
PLSfl 12/6 



PT.39 
PL81 
±'I.-2 
PL83 
PES4 

PL302 .. 
PL500 16/8 
PLiUl 15/ 
PY3-3 " 



17/G 
9/6 
6/- 
8/- 
8/6 

11/M 



I'YS3 
PYS'I 
PY81 
FYS-2 
PY'R3 



11/8 
11/6 
7/6 
7/6 
7/6 

7'r. 

m 



PY301 16/6 
PY800 10/6 
P17801 10/6 
TZ30 11/6 



E19 
E121 



10/6 
10/6 
12/6 
12/8 
14/- 
6/8 
10/6 
9/8 
7/8 
10/6 
10/6 
7/8 
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UC9-2 8/6 
UCF80 14/- 
L'OHSl 9/- 
LT41 13/6 



irv-3 

U143 

rag i 

U154 
i T 193 

U2«l 
i:3 19 



10/1. 

10/6 
9/6 
6/6 
8/6 

18/- 

12/- 
9/- 
7/6 



I'r-i.'j 
UL41 
LX84 
17T.12 
UY85 
W118 
Wt43 
WHO 
W727 

WD 130 11/ 
X18 11/ 
XSllf 85/- 
X143 12/6 
X150 11/- 
2145 11/- 
Z719 7/6 
ZD152 9/8 

tors-Transis- 
tors, Diodes, 
etc. 



1X21 B 


5/- 


IS 34 A 


8/- 


1XB1 


H 


1X253 


7ft 


1S459 


5/ 


IX 703 A 


tit 


IX 1.329 


Si- 


1X3075 


3/ti 


13111 


tj 


1S131 


413 


iaioi 


M- 


18420E 12/6 


187075 


4 >n 


2G301 


Kl 


2G30B 


7ft 


2G371 


4/G 


2G401 


u 


2G414 


5/ 


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4/ti 


2S257 


10/0 


2S388A 


SI/0 


2N505 


12 IH 


2N59fi 


7/6 


'2S097 


■r/n 


2X708 


4,'li 


2X?i>5 


7,'li 


2 N US 91 


•I'd 


2X1304 


HI 


2X1307 


m 



2X1132 12/6 
2X1755 15/- 
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2X2398 39/8 
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2X3707 7/6 
2X3819 12/- 
2S002 10/6 



88006 


15/- 


2S013 


mji- 


2S0I8 


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12/6 


S8839 


7/0 


E8S1S 


19/G 


233210 


10/- 


25H20 


■4-> 


80 A a 


h/« 


GO 0/5 


7/0 


AAZ13 


2/8 


AO120 


K,'H 


AC 128 


G/B 


ACY17 


N/H 


A0Y20 


&/- 


ACY28 


4/6 


AD 161 


Ki- 


AEY11 15/- 


AF114 


rn 


AFtlT 


w- 


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1(1/- 


Al'"239 


18/t! 


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10/- 


ASY93 


5/- 


ASZ21 


12/8 


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3S0/- 


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«/- 


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7/6 


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4/- 


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EY100 


4/6 


BYZ11 


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CRS1/20 


(2SF102) 


200 P.I.V. 


1 amp 




Tbyris 


;or 




9/ti 


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200P.I.V. 


3 amp 




Thyriatnr 




10/- 


CK707 


2/- 


CV2919 


2/- 


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CG12E 


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DD003 


3/6 


DK14 


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F8TI/1 


3/- 


GET 10 


-pr. 


cktidl 


6/- 


liETlL- 


4/- 


CET37 


5/- 


GKTiiT: 


6/- 


GKT88: 


5/- 


CETSSf 


7/6 


GKX54 


2/6 


GKX9315/- 


G.T6M 


4/G 


no 107; 


st- 


ilh!012 


ale 


JK'IOB 


15/- 


3K20A 


17/6 


M3 


1(6 


MAT 12 


7/9 


XKT2U 61- 



NKT214 4 

SKT218 6, 
MCT223 8 
N K 122;' 3 
NK'1'2'.'-. 6 
XKT2C5 9, 
NKT273 4 
NK l'2V 
XKT304 8, 
NKTS77 5, 
XKT777 8 
MFF10S 8, 
OA5 3 
OAtO 3 
OA70 8 
OA81 % 
OA90 2 
OA99 
1 1 A:! Hi 
OAZ204 8 
OAZ207 9 
OA2210 6 
OAZ213 6 
OAH242 4 
OAK247 4, 
OASS291 9, 
OC19 7, 
OtSS 
OC2G 
OG35 
OU42 
O044M 
0046 6 
0058 17, 
OC71 
OC75 
OC78 
OC81D 3, 
0081Z 8, 
OC83 
UC123 18, 
00141 18, 
OC171 
OO203 10, 

ot?joy 17, 

ORP12 8, 
RS34BF 9, 
SO 1171 15, 
ST 140 4, 
SVOl 15, 
8X63 8, 
8X043 3, 
8X 6 45 15, 
SZ5GA 
TE20 

TK25 

TKS'i 
TK41 
V A 1010 2, 
VA1027 81 
VA1068 8, 
YR35 6, 
VB9B 8, 
V405A IB, 

XAin 

X A 1(13 
X A 14 1 
XAI51 

X A I Ii2 
XA701 
Mi2<i2 
XB113 
XC101A S. 
XC163 
XC142 
XfllOl 

XI 

ZIJ4-3 
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■ l', = :^W1:'IJ:M:yH|-:» 






•FANE 122/17. 
12in. in 2 a WATT 
IBAVT DUTY 
HI-FI 
L o D ■ 
SPEAK- 
EltB. With 
high cttl- 
ciency 
Antia tropic 
FerrMe magnet. 
17,000 gauss. Imp. 3-5 ohms. Brand new 
am! guaranteed. Lint Trice £12. LDJD- 
AIR PBICE £8.18.0. r. * P. 5/6. 

E.M.I. COMBINATION 

LOUD SPEAKERS. 13J 

X Sim. Elliptical with 

3Jin. dia. Tweeter. Imp. 

8 ohms. Power iisn tiling 

ID watts. Brand new and 

guaranteed. List prire 

£8.5.(1. LIHD-AIR 

PRICE 69/6. i'. & T. 7/0. 

(Also available without 

tweeter 69/6. P- 4 P. 

7/8.) 

FANE 301 

3in. 

TWEBTEBS 

Imp. 3-5 ohms. 17,000 

gauss, IS watt. Brand new 

anil KiNtrant.^d. Liyl prior 

£3.15.0. LIND-AIR PRICE 89/6. P. ft V. 8/6. 

GOODMANS SPEAKER BARGAINS! 

Gin. 3 ohm, 15/8; Gin. 3 ohm, 29/6: Kin. 

3 ohm, 32/6; lOin. ohm, 65/-,- lOin. x filti. 

3 ohm, 32/6, TweeU-r. IB/6. P. & P. 3/B 

per Speaker. 



STEREO HEADPHONES 



Eldoy Stereo Sound as 
vi m have never heard It 
before. MODEL TTC. 
Cllll as illustrated. 
Soft padded earphones. 
Adjustable headband. 
. Impedance 8 ohms per 
phone. Frequency range 
25-13, 000c. p. s. With Lit. 
lead. Price 89/6. I'. * !'. 
A j*k Other simil ar t v pes 
available. AKAI ASESS. 
S ohms, £7.10.0. CORAL 
E102 10 ohms. 44,19.6. 
EAGLE SE1 IS ohms, 84/-. T.T.C. Stetho- 
scope 8 ohms, 49/8. P. & P, 4/B each. 



AUTO TRANSFORMERS 



Input 0-200, 2-20, 
Output 110V. 
BOW £1.7.6 
£1,17.0 
83.5.0 
£8,15.0 




70 W 

100 W 

I50W 

200W £3.5.0 

800 W £4.5.0 



1.000W £6.8.0 
I.50QW £15.15,0 
8,O0OW £18.10.0 
3.000W £25.10.0 
4.000W £34.18.0 
Q-30V, 1A 30/- 
0-30V, J A 17/9 
0-30V, 2A 37/6 
0-30V. 3A 42/- 



MAINS TRANSFORMERS 



Input 200/250T S0c/i. 

24V 3A £2.12.6 24V 8A £6.6.0 

24V 6A S3J.6.0 24V 12A £6,15.0 

Post extra. 

Mains and Output Transformer lis ts available 

on request. 



EXTENSION 
TELEPHONES 

ONLY 

37 6 




/ 

P. & P. 6/ 

Complete with lead, automatic dial 
numbered 1-10 and internal hell. Guaran- 
teed perfect working order. Made by 
famous manufacturer to G.P.O. speci- 
fication. 



StBOPPOSiTi 




TEAK FINISH PLINTHS 
with Fer?pt:x covercH gas. 
{for LABSO Si ens.). 
P. A- P. 12/8. 

Agents for Thnrens, Dual 
Goldring, etc. 



GARRARD DECKS 



3000 with Sonotonc 9TAHC Stereo Cartridge. . . . £9,19.6 
300 with Sonotonc 0TAHC Dlattioud atereo 

Cartridge , . £10.19,8 

ATfiO ML II Ism cartridge £13.19.6 

ATW MK. IT with Decca Deram St.-r.'n Cartridge £18.14.0 

8F.25 MK. II less cartridge £11.19.6 

SP.25 MK. II with Deeca Deram Stereo Cartridge £16.14.0 

AP.75 lesseartridge £23.4.11 

LAB.80 MK. II lees cartridge £24.19.6 

All plus P. A F. 12/6. 

Mono Cartridge 17/8 extra. Stereo Cartridge 22/6 extra 



2 J WATT AMPLIFIER 



An idea! basis for building your own portable 
record player. Just add speaker ami turntable 
and you will have an above-average model 
for a mere fraction of the cost. 2-3 watt printed 
circuit with control panel on dying lead. 
OX, OFF, TONE CONTROL AND VOIA'MI-;, 
colourful escutcheon, Brlmsr valves: EZSO, 
ECL82 and composite installation booklet, 
FBICE flC/_ P. ft F. 3/6 




BARGAllVLpFFER I FANTAVOX CASSETTE TAPE PLAVER 



Specially diwlgned to replay the well known and 
popular Musieasscttes — prerecorded tape cassettes 
offering a wide ehoice of all types of music from pop 
to classical. Up to 40 minutes of quality reproduction 
through built-in speaker. Simple uH/play and volume 
control*. Fully transistorised operating on 6 pen- 
light hatteritis. Modern compact styling with car|ilci;e 
socket and wrist strap. Size %\ x 4 j I 2ia. 

LDTD-AIR -rG 7 Cf ft Carr., pkg. and 
PRICE ■*- %fm I +J* \J 





6 Translator FM tuner. Frequency range 
88-103 He/s. Size Ss4s 2»la. Ucady built for 
use with most amplifiers, 9v battery operation. 
Complete with instructions. List Price gns. 



7 Gns. 



p. & p. 



MULTIPLEX ADAPTOR 

for above tuner giving Stereo 

Radio Reception £5.19.6 




controls, £6.18.6, Carr. 7/0. Metal 



UN EAR AMPLIFIERS 



Latest A.C. Mains Models offering highest quality 
at modest cost . 

LT68, All Transistor 12 watts Stereo. Inputs for 
Tuner, Oram., Mike, Separate Bass, Jfcebte, 
Balance and Volume Controls. £15.15.0. Carr. 7'fj, 
Teak ease £3.10.0 extra. 

PTA 15 (as lllus.l. All Transistor, 15 watts Mono, 
Inputs for Tuner, Gram, Mike. Cnitar. Bass, Treble 
and two volume controls. £15.15.0. Carr. 7/6, Teak 
ease £3.10.0 extra. LT45, 2 Valve 5 watts Monti. 
Inputs for Tuner, Gram, Bas», Treble anil volume 
lover 15/- extra. Full details Bi&ttt on request. 



9 In 1 ELECTRONIC KIT 




Build nine different project* from one basic 
tit — simple instructions, nn technical know- 
ledge required for you to build a Police Siren, 
Metronome, Morse Code Amplifier, Electronic 
Massage r, W/T Transmitter, Badio Tele- 
phone, One -transistor Badio, Two-transistor 
Radio. Electronic Music Kit. Complete- ]y 
safe, operated on Bv. PP3 battery. Hours of 
fun for boys and dads of all agce. Complete 
with all parts and simple step by step 
instructions, ONLY 69/6, P. & P. 5/-, 



MULTIMETERS 




MODEL TTC. 1001 
20.000 O.F.V. with 
overload protection. 
D.C. Volts 5, 25, 125, 
500, 2,500 v, A.C. 
volts 10, 50, 250, 
lOOv. D.C. MA 
250mA-5OA. With 
prods and carrying 
case. OHLY £4.5.0". 
P. A P. 3/6. 



MODEL TTC.1030. 
60,000 O.P.V. 
D.C, Volts, 0-3, 
12, 60, 120, 300, 
600, l,200v, A.C, 
Volts, 6, 30, 120, 
600, 1,200V. D.C. 
mA.O •3-300. With 
prods and carrying 
csae.ONLY£11.18.6. 
F, & P. 5/-. 




MOTOR 
BARGAINS 



Ideal for 
makers, 
players, 
decks, etc. 




6.3 D.C. Motor. 10,900 
r.p.m. at 230mA. IJin. 
X lit), diameter. Shaft 
lm. long x 3/64in. dia- 
meter, B/6. F. A P. 2/6. 



9 v. D.C. Gram deck 
replacement motor. 
2in. x I Jin. diameter. 
Shaft |ln. long x 
3/32in.,17/6. P. * F. 
2/-. TWO an / 
FOR « ,W /~ 
P. A P. 2/6 




SYNCHRONOUS CLOCK 
MOTORS 

Ceared (or 40 revolu- 
tions per hour. 230v. 
00 cycle, with 
mounting flanges. 
Size approximately 
lfin, deep x 2Jin. 
diameter. OSLT 22/6. P. * F. 2/0. 

SELECTOR DRIVE 



Numerous 
applications. 
Blect.ro mag* 
net and hrass 
tooth wheel, 
A switch 
u-afer and 
contacts are 
coupled to 
thig aud ar- 
ranged to be 
4- wj_y ^=^ J on lor 10 

pulses and ofl 
for 15, An Auxiliary contact is normally 
on hut off 1 in eTery 35. Complete with 
suppressor, resistors, plus series contact for 
continuous ope ration. Ideal window dis- 
plays, switching lamps, models, etc* I2v. or 
24v. D H C, Brand new and Wed t 12/6. 
P. & P. 2/6. 

ELECTRIC MOTOR 





Made by Crompton Farkmsoa. Single phase 
1th h.p. Motor 230 ,'250 v, 50 cycles. 1-3 amps. 
1,425 _ r.p.m. Continuous rating, Bpindle 
1| x ; in. dia. Overall size less spindle approx, 
8 x 6In. Perfect condition. A bargain for the 
work bench. ONLY 7S/6. Carr. 20/-. 

DELAY ACTION 
TIME SWITCH 



Made by Smiths. 
A.O, operation 
20 0/250 v. Double 
pole. Will give 
time delays from 

0-10 iniunteB, Sbe 3im. dia. x 3iin. kmg inc. 

(in, x 3/10ln. dta. spindle. iSAKGAIK PRICE 

17/8. F. & F. 2/6. 




163 



SENSATIONAL VALUE IN HIGH FIDELITY STEREO SYSTEMS 



SUPCKB 
30 watt SYSTEM'. 




AUDIOTRINE HIGH FIDELITY 

LOUDSPEAKERS Heavy cast 
construction. Latest high, efficiency 
ceramic magnets. Treated Cone sur- 
round giving low fundamental reso- 
nance. "D" indicates Tweeter Cone 
providing extended frequency rang-e. 
Impedance 3 or la ohms. Please state 
choice. Response 40-18,000 c.p.s. Ex- 
ceptional performance at low cost. 
5' 8W 49/9 HFIW 12' 15W 69/9 

8* sw 69/e liFianrj 14* jjw 79/9 

8' 10VV £4.19.9 HF126 12* 15W 89/9 
HFIOLD 10" 15 W £5.19-9 1IF11BO 13* 15 W 5 £fns. 




Consisting of CD Garrard Mk H SP25 4-spe ed Turntable with 
Pick-up. Heavy 12in, turntable hydraulic lowering- device 
and many other features inc. Plug in P.U. head. Fitted CS90 
P.U. Cartridge ready wired on plinth (baseboard). Fitted 
plugs for instant use. (2) Super 30 Amplifier fully wired and 
fitted in cabinet above. (3) Pairof Stanton HI Loudspeaker 
Units, Extremely attractive cabinets finished Satin Teak 
■ — - Veneer tinted Perspex' hinged' lid. Performance compara- 
ble with equipment at twice the cost and 
saving approx. £18 on above 77 fine 
units. Special inclusive price ,£ - u,li ' 
Terms: Dep, £19 and 12 mthly payments 
of £5. Total £73. Send S.A.E, for leaflet. 



HIGH FIDELITY LOUDSPEAKER UNITS 
Cabinets of latest styling Satin Teak op Walnut 
acoustically lined (an<l iiorted where appro- 
priate). Credit terms available on all units. 

00 RSET size 16 x 11 x 9in. Response 45- 
18,000 c.p.s. Rating 8-10 watts. Fitted 
Audiotrine HF810D speaker. CO 1Q Q 
Impedance 3 or 15 ohms. L " ,l3, « 
ST ANT0 N 1 1 IS s izelS x 11 xioin. Rating 
10 watts. Incorporating Audiotrine HF 
815 speaker with roll rubber surround 
and 15.000 1 ine magnet. High flux tweeter. 
Handsome Scandinavian design cabinet 
Response 30-20,000 c.p s. Impdnce 3 or 151 C fine 
ohma.Givessmoothrealisticsoundoutput. ■ u "'ia. 
D RC H ESTER size 24 x 16 x 10in. Fitted Audiotrine 
HF101D speaker. Rating 15 watts. Impedance 3 or 
15 ohms. Response 30-20.000 c.p.s. 1 y± Rn« 
Provides really pleasing sound quality. ,fc 2 «"*>■ 
GLOUCESTER size 25 x 16 x loin. I2in. High flux 
12.000 line speaker. Cross-over unit and Tweeter, 
Rating 10 watts. Smooth response 19X fine 
40-20,000 c.p.s. Impedance 15 ohms. "2 «■■»■ 




LINEAR TAPE IMU'l-.VMl'LTFEER. Type LP/1 
Switched Equalisation. Positions for Recording 
at liin.i 33 in.. 7: in. per set 1 ., and Playback. EMS 4 
Recording Level Indicator. Designed primarily 
as the link between a Magnavox Tape Deck and 
Hi-Fi amplitier suitable most 1 nj_ fine 

Tape Decks. Terms avuilalile. * u 2 u,,a * 



®z®%- 



R.S.C. TA6 6 Watt HIGH FIDELITY SOLID 
"\ STATE AMPLIFIER 

200-250 v. AC mains operated 
Frequency Response 30- 
20.000 c.p.s. -2dB. Harmonic 
Distortion 3% at 1,000 c.p.s. 
t~" Separate Bass and Treble 

lift' and 'cut' controls. 3 input sockets for Mike, 
Gram, Radio or Tape. Input selector switch. Output 
for 3-15 ohm speakers. Max. sensitivity 5mV. Fully 
enclosed enamelled case. 91 x 2? x 51 in. Attractive 
brushed silver finish facia plate 10 i x 31 in, and 
matching knobs. Complete kit of parts with full 
wiring diagrams and instructions. Carr. 7/6 

Or factory built with 12 months R fine 

guarantee. Post Paid 8 fins, u una. 




RECORD PLAYING UNITS 

Ready to plug into Amplifier 
DD? or Tape Recorder. Con- 
■" listing of Garrard SP25 

Mk II (with heavy turntable) 
fitted Hold n':i|r I h:-uj h i'^ mm. 
pliance ceramic Stereo/Mono 
cartridge with diamond sty- 
lus, plinth and cover. Nor- 
mally approx. £20, 22 GtlS 

RD7 Carr. 15/-. 

*" "As above but with 
Goldring Lenco GL68 Trans- 
cription unit and CS90 Car- 
tridge. Normally approx. 32 
gns. Carr. 15/-. 97J. fi n - 
ONLY £/ T UnS> 




AUDIOTRINE PLINTHS for 

Record 
Playing 
units. 
Teak 
finish 
cut for 
Garrard 
1000. 
2000. 

3000, ATS, AT60, SP25 or Gold- 
ring GLG8. Available with 
clear Perspex co- 
ver as ill. Carr. 7/6 
Or deeper type cut for TA12. 
Super 15 or 30 4 Cins. or with 
cover £8.19.11. Perspex cover 
sold separately at 3 gns. 
Limited number slightly 
damaged but repaired by 
Manufacturer. 39/9 to clear. 



Inc. Garrard 
SF25MkH Play- 
er Unit (with 
heavy cas t turn- 
table) on plinth, 
ready vrired. 
with plugs and 
fitted Goldring 
CS90 high com- 
pliance ceramic cartridge with diamond stvlus. Ass- 
embled TA12 Stereo Amp. in cabinet and Pair of 
Dorset Speaker Units. Total for above saving £13. 
Special Price AJ fine Carr. 
Perspex cover59/9 extra with above. Hl una. 35^ 
Terms : Dep £7.6 and 9 mthly pymts £5.3 (total £53. 13). 



RS0TA12 13 WATT STEREO AMPLIFIER 



FULLY TRANSISTORISED, SOLID STATE CONSTRUCTION 
IIIG1I FIDELITY OUTPUT OF Of. WATTS PER CEL4NNEJL 

Designed for optimum performance ,^= 
with any crystal or ceramic Gram 
P.U. cartridge. Radio tuner. Tape re- 
corder. 'Mike' etc. -k 3 separate' 

switched input sockets on each chan- II ! * ■#*. g^' .an, ■■'■ lB t- 
nel * Separate Bass and Treble con-li "-" ^5 -%3 i^ ?- 
trols -*r Slide Switch for mono use *\-li™- ■■ ~ ■ ~ , t 

Speaker Output 3-15 ohms * For \ "— ' — i^— * j" :: ' -i 

200-250v. A.c. mains + Frequency ~ " — ^^ 

Response 30-20.000 c.p.s. -2dB * Harmonic Distortion 0-3% at 1000 
c.p.s. Hum and Noise - 70dB *■ Sensitivities (1) 300mV (2) 'sOmV (3) 
lOOmV (4) 2m V * Handsome brushed silver finish Facia and Knobs. 
Complete kit of parts with full wiring diagrams and in- mm Carr. 
struct ions. Factory built with 12 rath gn tee 15 CSS. Or 11 7/9 
Deposit £4.16.0 and 9 mthly pyrnts. 89/- (Total 17 GNS.). ■ ■ GNS. 
Teak finish cabinet as above 73 6 or a> in .stereo svstem 4 tins. 



£5,19.11 



INTEREST CHARGES 
REFUNDED 

Sales settled 



Credit 
n 3 months. 



AUDIOTRINE HI-FI SPEAKER SYSTEMS 

Consisting of matched 12in. 12,000 line 10 watt 15 ohm 
high quality speaker, cross-over unit and twpeter, 
Smootli response and extended frequency range en- 
sure surprisingly realistic reproduction. C fin- 
Or Senior U watt inc. HF 126 ° UH5. 

15,000 line Speaker 6 Gns, Can-. 6/6 Carr. 5/9 

FR3b 3-S»eaker System inc. HF 122L 12in. 20 watt Bass 'speaker 
■■•-■■ 1 en roll rubber cone surround for very low fundamental resonance, 
5m. 10,000 lme middle rango speaker, high flux cone type tweeter, 
appropriate choke/eapaci tor cross-overs. Imped. 15ohms. Frequency 




response . 20-20,000 cp.s. Circuit and recommended 1 1 fine 
ae supplied, ONLY ' ■ UIIOi 



cabinet size s 



HI-FI 'SPEAKER ENCLOSURES T eak veneer finish. 

Modern design. Acoustically lined and ported. 

JE8 Size 20 x 11 x Sin. Gives pleasing results A fi,,- 

with any Bin. H1-F1 'speaker. * una 

SE8 For optimum performance with any 81 a, C fi nc 

Hi-Fi 'speaker. Size 22 x 15 x Sin. J una 

SE10 For outstanding results SE12 For excellent performance 

withlOmHi-Fi'spkr. n fine with 12in Hi-Fi 'spkr and 7 p~~ 

Size 21 x 15 I lOin. v una. Tweeter. Size2axl6xlQiin. * Ulla. 




Total cost of parts 
with detailed wiring 
diagrams & instruc- 
tions, in 1 
Carr. T.Z 3 Q 



R.S.C. TFM1 SOLID STATE VHF/FM RADIO TUNER 

*High-sensitivlty *200-3.'i0v. A.C, Mains opera 

lion.* Sharp A.M. Rejection. -jtDrift-free reeep- 

=^^_— — ' ii tion. A Output ample for any amplifier (approx. 

=-=^=-~^ '& 500 m. v.). ^Simple alignment instructions. -*-Out- 

ne Wl' ~— 1 -^~~ — ~rr^-J put available for fee<llng tuning meter. -^-Output 

10/- ■"« «•■■•** ^ j^_^^^_- £: =^^^l f or feeding Stereo Multiplexer. *Tuner bead 

Or factory built 1 using silicone Planar Transistors. -ycDesignetl 

165 gns. Or in Teak for standard SO ohm eo-axial input. Visually matching our Super 15 and 
finished cabinet as 30 amplifiers and of the same high standard of performance and reliability 
illustrated 191 gns. The pre-wired f tuning head facilitates speed and simplicity of construction 
Terms: Deposit £5 Frintod circuitry. Only first grade transistors and components used. A 
and 9 monthly pay- quality product at half the cost of comparable units. Stereo version, all 
ments £2. Total £23. parts 18 gns, Assembled 22* gns. Carr. 10/-. 



LID STAT 
INSTRUCT! 
SPECIFICATIONS COMPARABLE 
WITH UMTS AT ALMOST TWICE 
THE COST 



RS.C.$UP&ZlSMFiAMPUmm 



FUULYTRA\SISTOI(ISi:i)2lM).250v. A.C. Mains 
OUTPUT 10 WATTS It. M.S. cont. into 15 ohms 
15 WATTS It. M.S. cont. into 3-^ ohms. 
LATEST MULT.AIM) TRANSISTORS. AD149. 
AD149, OC12TZ. OC81Z. OC-H. OC44, OCaiZ, OC44, AC107. 
5 position i\T i i , si-:li-;< IOH SWITCH 
EQUALISATION to Standard R.I.A.A. and C.C.I.R, 
Characteristics for Grain and Tape Heads. 
FULL TAPE MONITOR INCS FACILITIES. 
SENSITIVITIES: Magnetic P.U, 4 mV. Crystal or 
Ceramic F.U. 400 mV, Microphone 4.5 mV. Tape Head 
2-5 mV. Radio/Aux or Ceramic P.U. 110 mV. 
FREQUENCY RESPONSE: ±2dB 20-20.000 c.p.s. 

TREBLE CONTROL : + 15dB to - 14dB at 10 Kc/S. NEG FEEDBACK : 52dB 
BASS CONTROL: +17dB to -15dB at 50 c/s. HUM LEVEL: - 75dB. 
HARMONIC DISTORTION at 10 Watts 1,000 c.p.s. 0-1%. mm 1 
Complete Kit of parts with full constructional details and | wit fine 
point to point wiring diagrams. Carr. 12/6 ■■•* una. 

Supplied factory built 151 Gns. Carr. 12/6. Terms: Deposit 4 Gns. and 9 | 
monthly payments 31/1 (Total £18.3.9). Or fitted in beautiful walnut or , 
Teak veneered cabinet as illustrated, 31 Gns, extra. 

ALL COMPONENTS ETC. ARE OP A HIGH STANDARD AND ■ 
SUPPLII l> !tV I..FA111MJ ItltlTlSlI MANUFACTL HERS. 




mR.S.C$UP€RZOST£fi€0AM/>Wm 



A DUAL CHANNEL VERSION OF THE SUPER 15 

Employing Twin Printed Circuits. Close tolerance 
Ganged Pots. Matched Components. CROSS TALK: 
— o2dB at 1.000 c.p.s. 
CONTROL: 5 position Input Selector, Bass Control. Treble 
Control. Volume Control. Balance Control. Stereo Mono 
Switch. Tape Monitor Switch. Mains Switch. INPUT 
SOCKETS (Matched Pairs). U) Magnetic P.U. (2) Ceramic or 
Crystal P.U. (3) Radio/Aux. (4) Tape Head/Microphone. 
Operation of the Input Selector Switch assures appropriate 
equalisation. Rigid 18 s.w.g. Chassis. Size approx. 12in, wide. 
3in. high and Sin. deep. Neon Panel indicator. Attractive Fas- 
cia Plate and Spun Silver Matching Knobs. Above facilities, 
etc.. except for Ganging and Balance Control, apply also to Super 15 
TTILSi: UNITS ARE EMINENT! A M ItAlIlF, FOR t SK WITH 
ANY MAKE OF PICK-UP OR MICROPHONE (Crystal, Ceramic, 
Magnetic, Moving Coil, Ribbon). CURRENTLY AVAILABLE 
SUPKRB SOUND OUTPUT QUALITY CAN BE OBTAINED BY 
USING WITH FIRST RATE ANCILLARY m rt -. 

EQUIPMENT. All required parts, point to point wiring I *f Rn^ 
diagrams and detailed instructions. Carr. 15/- ■ ** »*■•«*■. 

Unit factory built 27 Gns. or deposit £6.2.0 and 9 monthly payments 58/3. 
(Total £31.8.3). Fitted cabinet as Super 15 30 <ins Carr. 15/- or Deposit 
«i.2.(i ftii-ii h rv.--;Mh]y ^v;m, 64 - =T.. . I ir;-].i8.6>. Send S.A.E. for leaflet 



BRADFORD 10 North Parade, (Half-day Wed.) Tel. 25349 
BRISTOL 14 Lower Custle St. (Half-day Wed.) Tel. 22904 

B I R M I N G HAM 30 ' 31 Gt ' ^^^IT^^IZ T 

Station 021-236-1279 No ha If- day 
DERBY 26 Osmaston Rd. The Spot (Half-day Wed.) Tel. 41361 
D AR LI N GT0 N 18 Prleslgate (Half-day Wed.} Tel. 53043 



RSC 



HI-FI GENTRES ITD. 



32 High Street. (Half-day Thurs.) Tel. 56420 LEICESTER 

5-7 County (Mecca) Arcade, Brlggate (No half-day) Tel. 28252 LEEDS 

73 Dale St. (No half-day) fel. CENtral 3573 LIVERPOOL 



23S Edgware Road. W2 (Half-day Thurs,) Tel. PAD 1629 I flfLl nflHI 



MAIL ORDERS TO: 102 
Henconner Lane, Bramley, 
Leeds 13. No C.O.D. under 
£1. Terms C.W.O. or C.O.D. 

EDINBURGH 133 utm st. pwuw wed.) ™. wavene^ 5766 ^'^t/'tnl^ ^J^ 106 New p° rt Rd ( Half - d ^ WetJ ) Tel - « M6 M I D D LES B R0 U G H 

41 Blacken Street (Opp Fenwiefcs Store) K| C Ifll f» n CTI C UPON 

(Half-day Wed.) Tel. 21469 NCVVUMolLC TYNE 

13 Exchange Street (Castle Market Bidgs.) 

Open all day Sals, except High Holbein (Hall-day Thursday) Tel. 20716 



fi LASGflW 326 Ar a) r| e St. (No half-day) Tel. CITy41S8 

u u-i*» u w ■ ■ 403 Sauehi«h»M St. (Opp . Locarno) Tel , 332-1 572 

HULL 91 Paragon Street. (Half- day Thursday) Tel. 20505 



S/9 extra under £5. Trade 
supplied. S.A.E. with enquiries 
please. Hi-Fi Catalogue 4/6. 



96 High Holborn. WC1. Tel. HOL 9374 (Half-day Sat) 

60A-60B Oldham Street (No half-day) nflAMPUECTCD 
Tel. CENtral 2778 MANLHfcbT tH 



SHEFFIELD 



164 



AUDI0TR1NE HI-FI TAPE RECORDER KIT 

REALISM AT INCREDIBLY LOW COST Please send S.A.E 
CAN BE ASSEMBLED IV AN HOL'lt leaflet. 

ONLY 4 PAIRS (IF SOLDERED JOINTS PLUS MAINS 

Incorporating latest Magnavox Tapedeck. H igh quality 
Tape Amplifier with switched equalisation for each of 
3 speeds. High Flux P.M. Speaker, empty Tape Spool, 
Reel of Best Quality Tape and handsome Portable 
Cabinet of latest styling, finished dark grrey leather- 
cloth. Size Hi x 17 x 8 J in. and circuit. Purchased separ- 
ately would total approx. £:16. Performance equal to 
units in the £60-£7n class. Deposit 4 gns. and 9 monthly 
payments 59/6 (Total 29i ens). 4 Track Model 3 firns. 
extra. Carr. 19.6 




R.S.C. STEREO/20 HI-FI AMPLIFIER ,.,.,. vidino 

10/U WATT ULT11A LIVEARPl'NIM'ULL OUTPUT 

ON EACH CHANNEL. SUITABLE FOB "MIKE". 

GRAM, RADIO OR TAPE. (?) valves ECC83. (2) ECL86. 

(4) EZ81. Frequency Response: ±2dB 30-20.000 C.P.s. 

Hum Level: 65dB down. Sensitivity: 20 millivolts max. 

Harmonic Distortion: 0-2% ■*■ Four-posit ion tone 
compensation and Input Selector Switch. * Stereo/ Mo no switch. 
IvNcon panel Indicator. -A- Handsome Pcrspex Frontplate. ^-Separate 
Bass and Treble controls. Output transformers are highqualitv section- 
ally wound. Outputs for 3 and 15 ohms speakers. Complete set of parts, point- 
1 4 GnS to-point wiring diagrams and instructions. Or factory assem- 




Carr. 1Z'6 



bled with our usual 12 mths* gntee 19gns, Or Dep. £4.10.0 and 
9 monthly payments £2 dotal £22.10.0). Send S.A.E. for leaflet. 



R.S.C. A10 30 WATT ULTRA LINEAR HI-FI 




AMPLIFIER 



Highly sensitive, Push-Pull 
hiirh output, with Pre-amp./ 
Tone Control Stages. Performance figrures equal 
to most expensive amplifiers. Hum level — 70dB. 
requency response ± 3dB 30-20. OOOc/s, Sectionally 
wound output transformer. All first qrade 
components. Valves EF80, EF86. ECC83, 807 
807. GZ34. Separate Bass and Treble Controls. 
- - itivfty 12 millivolts so that any kind of 
Microphoncor l*ick-npi* suitable. Designed 
for Clubs. Sehools, 'Theatres, Dance Halls 
or Outdoor Functions, etc. For use with Electronic Organ, Guitar, String 
Bass, vlv. Grain, Radio or 'I'iiuc. Re?:-iTc E.T. and II. T. for Radio Tuner. 
Two inputs with associated volume controls so that, two separate inputs 
such as Gram and "Mike" can be mixed, 2Q0-250v, 50c, s A.C, mains. For 
3 and 15 ohm speakers. Complete kit of parts with point-to- 47 n_« 
point wiring diagrams and instructions, Carr. 12 6 * *■ una. 

Twin-handled perforated cover 25/-. Supplied factory built with EL34 
"■:<: ■■■ 1 valves. 1:1 mtmths' s mini lite e lor ]. r , kxi?, IlllllS: Deposit £4.13,0 
and Ei monthly payments 01 2S:9 (Total £17.11.9). :- ; .'t:d S.A.E. for leaflet. 




R.S.C. MIT 15 WATT HIGH FIDELITY AMPLIFIER 

DUAL PURPOSE P.A. or HI-PI. SOLID STATE 
CIRCUITRY, *3 input sockets. *2 vol, controls 
for mixing purposes. * Input Selector. -^Output for 
speakers between 3 and 15 ohms. -^-Separate Bass 
and Treble Controls. Suitable for Gram. Radio. Tape. 
Microphone, or Guitar P.U. For Vocal and Instru- 
mental groups. Frequency Response 20-40.000 c.p.s. —3dB. Hum level— 80dB. 
Harmonic Distortion 0-2% at 10 watts K.M.S. Operation on 20O-250V. A.C. 
mains. Size 91 x 21 x 5iin. Complete Kit of parts with Q fine Carr. 
comprehensive wiring diagrams and instructions. a u "*" 9/6 

Or Factory built with 12 mths. guarantee 13 gns. Carr. 9/6. Terms: Deposit 
£4 and 9 monthly pay- 
m en tsS5 SCTotal £1 5.9.G, ^^ j^jj TRANS FORMERS 




R.S.C, BASS-REGENT 

50 WATT AMPLIFIER 

Aa exception- 
ally powerful 
high quality 
all-purpose 
unit I or lead, 
rhythm, bass 
guitar, vocal- 
ists, gram, 
radio, tape 
* Two extra heavy duty 
I2in. Loudspeakers. 
•k Four Jack inputs and 
two Volume Controls for 
simultaneous use of up to 
four pick-ups or "mikes" 
plus Bass and Treble 
controls. 

dQ ■ I 13 nc Carr. 30/- or 
132 UHb. dep. £7.17.6 
and 9 monthly payments of 
£5.10.10. (Total 55 gns.). 
Send S.A.E. for leaflet. 
Also B30 Bass inc. Iain. 
iiw.Hpkr, 291 Ens. G15 lnc 
Viln. 30 w. Spkr, 19i gns. 

R.S.C. BATTERY/MAINS 

CONVERSION UNITS 
Tyne BM1 

An all-dry 
battery elt- 
m inator . 
Size 5ix4$x 
2in.approx . 
Completely replaces bat- 
teries supplying l-5v. and 
90v, where A.C. mains 200/ 
250v, soc.'s is available. 
Complete kit with diagram 
47/9 or assembled 59/11. 

SELENIUM I Tw! 
RECTIFIERSl (Bridged) 

All 61 13v, D.C. output. Max, 
A.C. input IB v. la. 3/11. 
2a. 8/11. 3a. 9/9- 4a. 12/9. 6a. 
15/9. 




14/11 
15/11 

19/9 
33 /a 
33/9 



FULLS GUARANTEED. Interleaved ana Imprer 
dated. Primaries 200-S50v. 50o/3, Screened. 
MIDGET CLAMPED TYPE 81 xSJ x SUn. 

■2oiDv,,fiOinA p 6-3v. 2a 

250-0 -250 v., 60mA, 6-3v. 2a 

FULLY SHROUDED UPRIGHT HOCNTDf B 

2gO-0-'250v. BOmA, 6'3v, 2».. 0-5-G-3v. 2a 

250-0-250v. tOOitiA, &M: 4n.,0-5-fi'3v, 3a, . 
30fl-O-30nv. 100mA, 6'3v. 4a.,0-S-G'3v, 3a. . . 
300-0-3(10 v. ISOniA, 6-3i% 4a, , c.t., G-3v, la. 

±'or Milliard S10 AuiplOler 41/9 

330-0-350 v, 1 OmA, 6 -3r. 4a. , -S-6 ■ 3 v. 3a . . . 33/9 
3.M-0-350V, 150mA, 6-3v. 4a., G-5-8-3V. 3a. . . 42/9 

425-0-425V. 200mA, <S'3v. 4ft. c.t., Sv. 3a «7/9 

425-0-42SV 200mA, SSv, 4a, 0-3v. 4a„ 5v. 3a. 89/9 
450-0-400V. 250mA, 0-3v. 4a„ c.t., 5v. 3ft. . . 79/9 
TOP SHROUDED DROP-THROUGH TYPE 
250-0-250V. 70mA, fl*3v. 2»„ 0-5-6-3v. 2a 19/9 

eso-o-aaov. 100mA, 6-3v. 35a a/9 

2u0-0-250v. 100mA, 6-3v, 2a., 6-3v. la 22/9 

350-0-350V, SOmA, fi-3v. 2a,, 0-5-6-Sv. 2a. . , . 83/9 
250-0-25OV. 100mA, R-3v. 4a,, 0-5*31'. 3a. . . 32/9 
30O-O-3OOv. 100mA, 0-3v. 4a„ 0-5-6 '3v. 3a. . . 32/9 
300-0-300v. 130mA, 0-3v. 4a., 0-5-S-3V. la. 

Suitable tor Mallard S 1 Amplifier 39/9 

350-0-350*-. 100mA, 6 -3 v. 4a., 0-5-6 -3v. 3a. . . 82/9 
350-Q-350V. 150mA, 8-3v. 4a., 0-5-S-3v. 3a. , , 39/11 
FTLAMENT or TRANSISTOR POWER PACK Types 
0-3t, l'5a. 6/8; 6-3v. 2ft. 7/8; 6'3v. 3a. fl/B; a-Sv. 
6a. 19/9; 12v. la. 8/9; 12v. 3a. or 24v, l-5a. 19/9; 
0-9-lSv. IJa. 15/9; 0-12-S5-42v. 2a. 27/9, 
CHARGER TRANSFORMERS 0-9-15v. IJa. 13/11; 
2;a. 18/11; 3a. 18/11; 5a. 21/11; 6a. 25/11; 8a. 31/11 
AT/TO (Step TJP/Biep DOWN) TRANSFORMERS 

O-llO/13Ov.-3OO-2SO-20Ov 50-80 watta 14/9 

150 watts, 29/llr 250 watts 49/9; 500 watts 99/9 

OUTPUT TRANSFORMERS 

Standard Pentode 3,000 Q i>r 7.000 fi to 3 Q . . 7/9 

Fttrti-rull 8 watts El£4 to SO or 15 fl 11/9 

Po5li-PulllOwatU6VrtECL8Sto3,5,8orl50 21/9 

Push-Pull ELS4 to 3 or 15 ft 10-12 watts 19/9 

Fusli -Pull Ultra Linear fur lluilard 610, etc. 35/9 
Push-Pull 35-18 watta, sectionally wound 0LG, 

KT86, etc., for 3 or 13 Q 29/9 

Push-Pull 20 watt high quality sectionally 
wguiidEL34, 6L6, KT6I) etc. to 3orl5fl ... 55/8 
SMOOTHING CHOKES 

150mA,7-10H,25OJl 12/9; 100mA, 10 If, 200 O 9/11,' 
SOmA, 10H, 350 Q 7/9; 60 mA, 10H, 400(1 4/11. 



R.S.C. COLUMN SPEAKERS covered in two- 
tone Rexine/Vynair. ideal Tor vocalists and 
Public Address. 15 ofem matching. Type C48, 2a- 
39 watts, FittedfourSin. hieh flux 7watt speakers. 
Overall size approx, 42 x 10 x Sin. Or deposit 44/- 
and 9 mthly pmts 34/9 (Total £18.1.6) Carr. 10/-. 
Type cm, 40 watt " 




15 Gns. 



Fitted four 12in. 12,000 line 10 watt yy f; n q 
speakers. Overall size 56 x 14 x 9in, approx. Carr. IS"- tm£ - u,, «" 
Or Deposit £3.13.0 and 9 monthly payments of 50/- (Total £26.3.0). 

30 WATT Hi-Fi AMPLIFIER 

fop Guitar, Vocal or Instrumental Group 

A 2 Input, 2 volume control Hi-Fi unit with 
Separate Bass and Treble controls. Peak rating 60 watts. 
Latest valves. Strong Eexino covered cabinet with 
handles. Attractive black'gold perspex facia. Neon 
indicator. For 2C0-250v. A.C. mains. 1 o fino Carr. 
;■'•;)■ 3 or :.i ..Urn spiH-i.l;iTS. Send «.A X. lo "lib. 12 e 
for leaflet. Deposit 3 khs. and 9 monthly payments of 39/8 (Total £21). 




12in. HIGH QUALITY LOUDSPEAKERS 

In Teak veneered or Itexine covered Cabinets 

10 Watt 12.000 lines B n ne 20 Watt 12.000 lines R Hnc 

3 or 15 ohms a UII&. 3 01 , i5 0hma O Ullb. 



Limited number of heavy duty 
units at fraction of list price 15 
ohms impedance. Brand new. guaranteed. Terms available over £8, 



LOUDSPEAKERS 




13in, 10 watt 13in. 30 watt 
HIGH FLUX Dl'ALCONE, 



59/11 



£5.15.0 



12in. 30 watt 
DUAL CONE 

IE6.19.9 *"£; 



15in. 40 watt 
DUAL, CONE 

1 1 nnQ Normally 

1 i gns. £18 appr 



FANE 
'POP' 100 

•SSfpf LOUDSPEAKER 

18'TDOWattfgH 

Fantastic power 
handling. Guar- 1 Q fine 
anteed 2 years. ' a "»J 



R.S.C. GRAM A5IPI.IF1EK KIT. 4 watts 
output. Negative feedback. Controls: Vol.. 
Tono and Switch. Mains operation 200-250v. 
A.C. . Fully isolated chassis. AO/II 



Circuit etc. supplied. 



ONLY 



POWER PACK KIT consisting of Mains 
transformer. Metal Hectifior. Electrolytics, 
smoothing choke, chassis and circuit. 200/ 
250v. A.C. mains. Output 250v. 77/11 
eomA 6-3v. 2a. Supplied with case "/ " 
in lieu of chassis 26/11. Or assembled 39/11, 



R.S.C. 4/5 watt 

AS HIGH GAIN AMPLIFIER 

A highly-sensitive 4-valve quality amplifier for the 
home, small club, etc. Suitable for all crystal or cera- 
mic P.U. heads and most "mikes". Separate Bass and 
Treble controls. Hum level 71dB down. Negative Feed- 
back 15 dB. For A.C. mains 200-250 v. Speaker output 
£4. 17 9 3 ohms. Complete Kit with point-to- 
1 * .»» point wiring diagrams and instructions. 




CONCORD 
RECORDING 



TAPES 



3 in. Std. 


3/11 


5 in. D.P. 


15/- 


3 in. LP. 


4/11 


5| in. LP. . 


15/- 


3i in. T.P. . 


12/6 


5% in. D.P. . 


19/6 


5 in. Std. 


10/- 


7 in. LP. 


18/- 


Bin. LP. 


12/6 


7 in. D.P. 


22/6 



These tapes are top quality and not cheap sub- standard. 
Post 1/6 per tape. Post free on 4 tapes or more. 

TRANSISTORS at bargain prices! 



OC22 


9/6 


OC77 


4/6 


AC127 


3/6 


BCY34 5/9 


OC23 


10/- 


OC7S 


4/- 


AC128 


3/6 


BCY38 5/9 


OC25 


9/- 


OC78D 


4/- 


AD140 


10/6 


BFY50 5/9 


OC26 


9/6 


OC81 


3/6 


AF114 


5/3 


BFY51 4/6 


OC28 


10/- 


OC81D 


3/6 


AF115 


5/- 


BFY52 5/9 


OC30 


10/- 


OC82 


3/6 


AF116 


5/- 


BYZ12 5/3 


OC35 


12/6 


OC820 


3/6 


AF117 


4/6 


BYZ1 3 5/9 


OC36 


12/6 


OC84 


5/6 


AF118 


4/- 


BYZ16 10/- 


OC38 


12/6 


OC123 


5/- 


AF119 


4/- 


GET103 4/6 


OC44 


3/6 


OC169 


4/6 


AF125 


4/6 


GET113 4/6 


OC45 


3/6 


OC170 


4/6 


AF127 


4/6 


GET116 7/6 


OC46 


4/- 


OC171 


4/6 


AFZ12 


6/6 


GET887 5/- 


OC70 


3/6 


OC172 


4/6 


BCY10 


5/3 


GET889 5/- 


OC71 


3/6 


OC200 


7/6 


BC107 


8/3 


GET890 5/- 


OC72 


3/6 


OA81 


2/6 


ESCY12 


5/3 


GET897 5/- 


OC75 


3/6 


AC 107 


6/6 


BCY33 


B/- 


GET898 5/- 


OC76 


4/- 


AC 126 


3/6 










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and 


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for c 


Dmplete transistc 


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941 WIMBORNE ROAD, BOURNEMOUTH 
Tel. 59B65 




165 




PRACTJCALy^ "V 



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166 



PRACTICAL 

WIRELESS 



VOL 44 No 3 



issue 737 



JULY 1968 



TOPIC OF THE MONTH 



NEWS AND COMMENT 



What is "standard"? 

WE often hear that commercial radio sets use 
"standard circuits". Superficially this may be 
true, but a study of current models will uncover many 
variations in style and design. It is reaily quite remark- 
able that six makers can come up with six different 
approaches to the design of, say, a seven transistor 
portable. Except in fundamental aspects, there is no 
such thing as a standard circuit outside the pages of a 
textbook. 

This will become abundantly clear when called upon 
to service some of the offerings from the Orient and 
elsewhere and there is no circuit diagram available. 
Often it is necessary (and is a useful exercise anyway) 
to trace out the circuit from the chassis. The basic stages 
should be easily located and from then on it is simply a 
matter of patience to fill in the gaps. 

This is one activity in which the amateur scores over 
the professional. A technician trying to earn his bread 
and butter (and maybe a little jam) usually has little 
time to probe around a strange circuit while he could be 
engaged on more profitable work. The amateur, on the 
other hand, is not too concerned with- the time factor 
and is relatively free to indulge his curiosity. And he can 
also learn a good deal into the bargain, for no amount 
of textbook swatting will compensate for practical 
work on actual receivers. 

Yet, purely practical work will not advance a 
constructor's knowledge unless he takes the trouble to 
work out not only what a circuit is but what it does, 
and how. He should find out why a certain component 
is placed in a particular part of the circuit and why it 
has a certain value or rating. He should also be in- 
terested in knowing what might happen if the 
component breaks down in any way. 

So, next time you find yourself with an unfamiliar set 
to look over, think of it not as a chore but as an oppor- 
tunity to expand your knowledge and expertise. Such 
activity should be part of any enthusiast's education I 

W. N. STEVENS— Edit or. 



Leader 1 67 

News and Comment 168 

Audio Fair 1968 174 

On the Short Waves 

by Christopher Danpure and 
David Gibson, G3JDG 1 81 

Practically Wireless 

by Henry 1 93 

Letters to the Editor 200 

Club Spot — Allerton and District 
Scout Radio Hobbies Club, 
G3TZR 207 



CONSTRUCTIONAL 

Portable Keyless Organ 

by G. W. Hardy ^ 1 70 

The "Clubman", Part 7 

by J. Thornton -Lawrence, 
GW3JGA , 176 

Simple Receivers for Beginners 

by T. Simon 1 85 

The Steptron 

by H. T. Kitchen 1 88 

V.F.O. for the Ten- Fifty Trans- 
mitter 
by A. S. Carpenter, G3TYJ 208 



OTHER FEATURES 

Repairing Radio Sets, Part 4 

by H. W. Hefiyer 1 94 

Five Steps to Hi-Fi, Part 3 

by fain Smith 203 

AUGUST ISSUE WILL BE PUBLISHED ON JULY 5th 



All correspondence Intended for the Editor should be addressed to : The Editor, "Practical Wireless", George Newnes Ltd., Tower House, Southampton Street, 

London, W.C.2, Phone: TEMple Bar 4363. Telegrams: Newnes Rand London. Subscription rates, including postage: 36s. per year to any part of the world. © George 

Newnes Ltd., 1966. Copyright in all drawings, photographs and articles published in "Practical Wireless" Is specifically reserved throughout (he countries signatory 

to the Berne Convention and the U.S.A. Reproductions or imitations ol any of these are therefore expressly forbidden. 



167 



heuis mid commEnT 



MICRO-MICRO 




Yes, we know it's a photograph of a "tanner" but look 
at the little black thing next to the coin. This is a sub- 
subminiature micro switch and the makers, Honeywell, 
claim that this range is the smallest in the world. Certainly 
an indication of the way in which the discreet components 
are slowly shrinking to keep pace with the semiconductor 
miniaturisation programme. Statistics of our pin-up are: 
Operating Force — 5oz. max.; Release Force — 1oz. min.; 
Pretravel — 0020in. max.; Overtravel — 0'004in. min.; 
Differential travel — 0005in. max.; Weight— 1 /28th of an 
ounce. Temperature range — minus 95°F. to plus 375°F. 
(Phew!). 

The electrical ratings given on the spec, sheet are very 
comprehensive. The d.c. ratings: 30 volts at -7A resistive; 
4A inductive (sea level); 2-5A inductive (50,000ft); 24A 
max. surge. For a.c: 115/250 volts at 7A resistive and 
inductive; 20A surge. 

The switch itself is a single-pole double-throw snap- 
action type. Further information from Honeywell Controls 
Ltd., Great West Road, Brentford, Middlesex. 

HAR YER GOT A LIGHT BOY? 



OH DEAR! 
The gentlemen of Jodrell Bank, home of Britain's giant 
radio telescope, are unhappy. Signals are being received 
which just can't be explained and will not fit into any 
physical theory put forward so far. Until quite recently, 
the only spectral line known was that emanating from 
Hydrogen at around 21 cms. Now, at frequencies in the 
1,600Mc/s region from OH sources, come other spectral 
lines whose intensities don't coincide with what theory 
dictates. 

The energy from these sources a/so appears to be 
polarised in various planes which again causes much 
frowning among radio astronomers. However, a recent 
set of measurements carried out in conjunction with 
American radio astronomers looks like proving fruitful. 
To date, the information from these experiments is still 
being carefully sifted and interpreted, but it could be 
that those giant concave steel eyes have a/ready taken 
the first step to solve another of those mysteries of 
space. Some people have seriously suggested that the 
signals might be intelligible, but we are reserving judge- 
ment. 




A new re-styled pack of their Match-Melting 
Multicore Tape Solder has been marketed by 
Multicore Solders Ltd. of Maylands Avenue, Hemel 
Hempstead, Herts, It is supplied in cut lengths 
sufficient for about 50 joints. This tape solder can 
be used without a soldering iron or extra flux, and 
can be applied with the aid of a match. The recom- 
mended retail price is 2s. 6d., matches extra — of 
course! Further details may be obtained from the 
manufacturers. 



FERGUSON FUTURA II 




The Futura II is Ferguson's first transistorised mains 

operated table radio. It preserves the low, long look and 
is styled in rosewood. For the size -conscious reader, the 
manufacturers confess to the following dimensions: 
221 x S x 5% in. including feet. 

The controls all have spun aluminium caps with polished 
edges. The two large knobs are on/off and volume, and 
tuning, while the two smaller ones are bass and treble. 
Five push-buttons function for v.h.f., a.f.c, long, medium 
and short waves. Coverage on v.h.f.S7-5 to 108Mc/s, 
while long, medium and short waves are covered in three 
segments 1110-2020, 185-565 and 17-50 metres 
respectively. 

Sockets are provided for a.m. and f.m. external aerials 
although the set boasts its own internal Sin. ferrite rod 
for a.m. An internal f.m. aerial using the mains lead is 
also fitted and may be disconnected when an external 
aerial is used. Output from the 5 x 3ln. 750 speaker is 
1-5 watts (speech and music rating). 

The Futura II requires 200-250V. a.c. 50cfs, 5 watts, 
has ten transistors and six diodes, and if you want one 
will cost you £41 10s. Od. 

Also from Ferguson is the Autotwin portable, suitable 
for home or car. A nine transistor circuit covers long and 
medium waves with 700mW output. 



168 



news mid commEni 



THE ELECTROWR1TER 





This device enables one to send a drawing or sketch 
over the telephone or radio. One writes with a ball-point 
pen on regular paper as on a note pad, and as the pen is 
moved, the remote receiver(s) instantaneously and 
faithfully reproduces the copy as it is written. No ex- 
traneous power supplies are required since the instruments 
are fully transistorised and self-contained. 

The electrowriter can be attached to a telephone system 
permitting alternate written messages and voice service. 
The device is an electro-mechanical pantograph giving 
the facility that one can write to other points by remote 
control. This is done by creating two frequencies trans- 
mitted down .a pair of wires compositely, one of which is 
governed by horizontal movement and the other by 
vertical movement. This gives true analogue service 
unlike a teleprinter which relies on single pulses and is 
therefore a digital device. 

The receiving unit has a mechanical response to a 
varying frequency on the line. The input is filtered in such 
a way that it splits the composite signal into two distinct 
frequencies each of which is then able to operate the 
vertical and horizontal pantograph motors, which in turn 
operates the pen. The action of the pen nib is achieved by 
frequency modulating one channel, which is then detected 
and converted to "pure" d.c. to operate a solenoid which, 
by mechanical linkages, causes the pen to touch the paper. 
This sequence of events is touched of at the transmitter 
by the operation of a gravity switch within the stylus and 
thereafter by a spring loaded plunger which operates 
the pen-down mechanism. 

The receiving machine is inactive until a signal appears 
at its input, which operates a "squelch" relay which brings 
the whole device to life. Since both horizontal and 
vertical frequencies (1310-1490 and 2060-2340c/s) are 
within the voice bandwidth, whenever voice reception is 
possible this system will operate. You'll be able to send 
those circuits by telephone soon! 



RADIO LEEDS 
Construction is in progress on the transmitter 
building for BBC Radio Leeds which should be on 
the air this month. The building is in the grounds of 
Meanwood Park Hospital, about 3i miles north of 
the city. 

The station will operate on v.h.f. 94-6Mc/s, 
horizontally polarised and will cover the whole of 
the city. The local programmes will be originated 
from the headquarters of BBC Radio Leeds at 
Merrion Centre. Reception is expected over an area 
bounded by Pudsey, Arthington, Scarcroft, Swill- 
ington and Lofthouse. 

FLUID 101 

"A transistor radio was completely immersed in water and 
obviously ceased to function. Afterwards it was sprayed 
with Fluid 1 01 and recommenced working within seconds". 
"An electric light bulb was connected with bare wires, 
immersed in water after spraying the wires with Fluid 101 
and lit quite normally". This is what Special Products 
Distributors Limited claim for a can of Fluid 101, which 
costs 9s. 6d. for the 6oz. size. Almost worth getting a small 
can just to see — isn't it? 

METHOD 101 

Have you ever wondered 
just how much testing 
goes on to ensure that 
your electronic compo- 
nents are reliable? Ray- 
theon Company of 
Lexington, Massachusetts, 
really go the whole hog. 
If you were one of their 
new gold- plated precision 
spark gaps (for instance) 
you would have been 
subjected to the following shock test described as 
"method 205C": J5G's for 11ms; 18 impacts in three 
mutually perpendicular axes. Had enough ? Well, there's 
still the vibration test — 10 to 300c fs along each axis for 
30 minutes, ambient temperature check from minus 55°C to 
plus 85 C 'C and just to finish you off — salt spray testing "... 
in accordance with method 101". 

The photograph shows three who made it — well done 
chaps! (Bet you readers are glad you're on the other end 
of the soldering iron), 

BROADCASTING CONVENTION 
The International Broadcasting Convention is to 
be held in London from 9 to 13 September, 1968, 
at the Grosvenor House Hotel, Park Lane. The 
Television Conference, already announced by the 
learned societies for 1968, is incorporated within 
this Convention at which a wide cross-section of 
the latest broadcasting equipment will be shown. 
Further information from E.E.A., Berkeley Square 
House, Berkeley Square, W.I. The Convention 
Secretariat address is to be: The International 
Broadcasting Convention, Savoy Place, Victoria 
Embankment, London, W.C.2. 

169 






G.W. HARDY'S 



portable 




ORGAN 



TRANSISTORS are used throughout this instru- 
ment, which is complete with power amplifier 
and loudspeaker. Despite its simplicity and low 
cost, the tone obtained is of great appeal, and com- 
pares with the solo voice of an expensive commercial 
electronic organ. Keys are not always easy to obtain 
and then will need altering and adapting to the new 
instrument. The method used by the author in this 
instrument, is a series of small metal plates, arranged 
in the usual layout of standard keys, so that it is 
easy to recognise and select any required note. 

Two wands terminating with a contact stud are 
needed, one for each hand. When the contact makes 
with any plate, the note generator starts oscillating 
at the previously tuned pitch of that note. Having 
two wands makes for smooth or legato playing The 
switch on wand No. 2 disconnects the preamplifier, 
but a sound is still produced provided contact is 
still made with that plate, but slowly decays while 
capacitor CI 3 Fig. 2 discharges. For normal playing 
the switch is kept closed with the forefinger. The 
metal plates are kept very close to each other, so 
that the wand contact can freely glide from one to 
another. 



Solo Organ Prototype 

The system of tuning used in the new instrument 
was experimentally tried out in the author's prototype 
of the organ described in an article which appeared 
in the February, March and April 1965 issues* of 
P.W. Readers who have built this instrument will 
be interested to know that the new tuning method 
has proved very satisfactory while in constant use 
for a period of over 12 months. Constructors will 
only need to remove the tagstrip containing the tun- 
ing resistors, and subsitute the tuning device to be 
explained later in this article. The vibrato used in 
this new instrument is a true vibrato, which means 
that the frequency of the sound is modulated, and 
is obtained from a one transistor phase shift oscilla- 
tor. Another toggle switch was fitted alongside the 
original vibrato switch, and room found inside the 
case to accommodate a PP3 9 volt battery. The bat- 
tery positive is taken to the common pdsitive, nega- 
tive through the new on/off switch, and then to the 



170 



oscillator panel. Output from the capacitor C5 (Fig 
1) is taken direct to base of Tr3 Fig. 1 (Feb 1965 
issue). 



The Note Generator 

A multivibrator circuit (Fig. 1) has been used 
again, as it is very accommodating and easy to set 
up. What other oscillator will give over three octaves 
of musical notes while only changing one resistance! 
With the components' values given a range of three 
octaves will be comfortably covered, that is from C 
one octave above middle C and down three octaves 
to C in the bass, a most useful range. A limiting 
resistance, R7 should be altered if necessary so that 
top C will be in tune when the moving arm of the 
tuning control VR3 is at half travel. Do not use 
lower value than 10kH or Tr3 will pass excessive 
current, 15kfi should be about right, a lower value 
will raise the pitch, and a higher one lower the pitch. 
Provision has been made in the layout of panel Fig. 
2 for R7 to be experimentally tried out before finally 
soldering to the two tags provided. 

Unless the constructor has another keyed instru- 
ment to give the pitch C (C above middle C on the 
piano), a tuning fork or pitch pipe becomes neces- 
sary. One can be purchased from any good music 
store and must be marked "C international or 
Standard Pitch". The vibrations are 523-25c/s 



Vibrato 

In Fig. 1 will be seen the circuit for the phase shift 
oscillator. It is important to use a high gain tran- 
sistor, in order to maintain oscillation. The OC72 
used was to hand and works very well. An OC45 
and white spot germanium transistor have been satis- 
factory. VR1 alters frequency slightly, and should it 
not cover the requisite range of 5 to 7c/s, R3 
6-8kn, can be varied slightly in value. In the layout 
two tags have been left for an experimental try-out 
VR2 slightly alters depth of modulation, and should 
be placed about half-way when setting up. Both 
controls should be midget or skeleton preset types. 



Contact plates Contact stud igp ^gggg J y;- . v j ,r , - 

/ ^T~~~^*^ A A* B 




ftp. 7: Circuit of the vibrato (phase shift) oscillator with variable speed and depth control, and the three octave note generator. 



The preamp Fig. 2 is a 
common emitter amplifier. 
The purpose of the 25fl 
resistance Rll, in series 
with the expression control 
VR4, is to prevent the 
sound being completely 
turned off, leaving it pos- 
sible to play very softly. 
The sustain switch, S3. 
enables the sound to 
slowly decay, the duration 
being fixed by the capacity 
of C13. The SOfxF speci- 
fied is quite satisfactory. 
and gives some useful 
effects. R17 is to absorb 
make and break clicks. 

The output stage has 
been designed around an 
AD 140 transistor (cost 
about 10s.) instead of 
using the more conven- 
tional Class B push-pull 
amplifier, which has many 
more components and 

more complicated wiring. The main advantage of the 
latter is of course in the battery current economy. 
However, this is more of a consideration when used 
in a radio set, which might be on for long periods, 
in our case, the instrument would normally be used 
for shorter periods, and it is up to the player to 
make a habit of switching off at every opportunity 
after and between the intervals of playing. There is 
no warming up period to wait for when switching 
on again. The consumption is 40mA, and a 4-£ volt 



Pre-amp and control circuit 




Power amplifier 



Fig, 2: Pre- amplifier and control circuit plus power output stage. VH4 is the expression (volume) 

control. 

fiat torch battery will give good long service with 
care. 

In the rather unusual output stage, the bias for the 
AD 140 is derived from the driver emitter direct con- 
nection. The driver being a p-n-p transistor ensures 
correct polarity. Negative feedback is taken via R19 
to the base of Tr5. This simple amplifier gives good 
quality musical output. 

The contact plate board is made from a piece of ex- 
terior quality hardboard, which is oil hardened during 



171 



manufacture and much harder than ordinary hard- 
board, but very little dearer. A suitable off-cut may 
be obtained from a shopfitter or builder. The size is 
18 x 54 in, and is fitted with metal plates which form 
the "keys". At the rear of the board is a fin. wide 
strip of the same hardboard, divided into 36 equal 
spaces. Each one, after treatment, will provide a 
variable resistance to tune each note, the soldering 
tags on the resistance strip are connected and wired 
through a small hole in the hardboard to the tag 
fixed by a screw to its respective plate. On the 
extreme right is a simple made up on/off switch, 
the arm of which, when moved to the left, makes 
contact with the countersunk head of a screw con- 
nected underneath with the top C screw. In the on 
position, top C will sound continuously, while the 
preset tuning control is adjusted into tune with a 
tuning fork or other reference. 



Pane! Wiring 

Knowledgeable constructors will have their own 
ideas about wiring, but the method used by the 
author has proved straightforward, alterations are 
easily made, and components can be salvaged with 
useful lengths of lead-out wires intact. Assemble all 
the components and straighten out the wires, which 
are then cleaned bright. With a small tapering pair 
of pliers, place against the body of the component, 
so that a lin. of wire is in the grip of the pliers, now 
with the component values shown uppermost, the 
wires are bent down at right angles. Cut a piece of 
cardboard same size as the panel and mark position 
of tags. With a pair of dividers measure off the dis- 
tance apart of the right angle bends, and using the 
lay-out drawing as a guide, impress on the cardboard 
where the component will be fixed. When finished 
the cardboard can be laid upon the panel and the 
impressions marked through with a sharp awl, these 
holes are then drilled with a -rVin. drill. 

After this, the wires are pushed through the holes 
and bent over towards each other, with the compon- 
ent held tightly on the panel. Wires are snipped 
off leaving a £in. stub, under which connecting wire 
is placed, and stub pressed down hard to grip ready 
for soldering. In some cases leads will be long enough 
to orientate and place under the wire of the compon- 
ent to which it is to be connected. Sleeving should 
be used as necessary, and transistors wired in last 
with their full length of lead-out wires. A i-in length 
of tight fitting sleeving should be put on transistor 
base leads and pushed up as far as possible. This will 
assist in identification and prevent possible shorting 
of leads. The tip of each transistor wire is cleaned 
and tinned while being held in a pair of pliers. 

The A DMO transistor is bolted down flat on to 
the panel, after making holes to take the stout base 
and emitter pins. The metal body is the collector, 
and when wiring up, terminate the lead to the col- 
lector with a soldering tag to fit on the bolt and 
tighten up with a nut. Observe the usual precautions 
when soldering transistor leads, and those of small 
electrolytic capacitors. Preparatory cleaning and tin- 
ning is a great help to good soldering. To assist in 
the external wiring to panels, it is recommended that 
they be marked with a sharp-pointed awl the legends 
as marked on Figs. 3 and 4. Correct battery markings 
are important. 



• components list 



Resistors : 




"I 


Rl 


6-8kQ 


R13 


68kO 


R2 


6-8RQ 


R14 


10ktl 


R3 


6-8ktl 


R15 


ikQ 


R4 


47QkQ 


R16 


6-8kH 


R5 


3-9kfl 


R17 


1kD 


R6 


22kQ 


R18 


6 8kQ 


R7 


15kO see text 


R19 


39ka 


R8 


27kQ 


R20 


470 1W 


R9 


2 2kQ 


VR1 


5kfi preset 


R10 


47 k a 


VR2 


1MQ preset 


R11 


250 


VR3 


5kQ preset 


R12 


4-7kD 


VR4 


5kQ Log. • 




All I Watt except R20 



Capacitors: 

C1 VF electrolytic 

C2 1 ^F electrolytic 

C3 1 /aF electrolytic 

C4 1 fiF electrolytic 

C5 0'1/tF paper 

C6 25//F electrolytic 

C7 005itF paper 

C8 0-0 VF paper 

C9 00 VF paper 

C10 0-25f*F paper 

C11 10mF electrolytic 

C12 50^F electrolytic 

C1 3 50f*F electrolytic 

C14 O'VF paper 

C1 5 1 0OjuF electrolytic 

Electrolytics all 1 5 or 25V wkg. 

Transistors: 

Trl OC72 

Tr2 OC45 

Tr3 OC45 

Tr4 0C71 

Tr5 0C72 

Tr6 AD140 

Miscellaneous: 

One double pole on/off switch; two toggle on/off 
switches; four 4i Volt flat flash lamp batteries; 
hardboard (exterior) 1ft. 6in. x 6in.; phosphor bronze 
draught excluder strip; 6ft. length stainless steel |in. 
wide (polished on one side); thirty-seven double 
ended tags; forty single ended tags; six ^in. wood 
screws for top fixing; forty ^in. 6BA round head bolts 
and nuts; thirty-seven Jin. 6BA cheese head bolts 
and nuts; gin. and 1 in. panel pins; Bostic No. 1 
adhesive; L.S. covering material; carrying handle; 
plastic off-cut 1ft. 6in. x3in.; 6ft. 6in. of Jin. square 
(ramin wood); 5ft. of ^in. square (ramin wood); 
4ft. of 3in. x£in. wood; paxolin -jfe-in. thick for 
panels; sheet aluminium; 6in. of thin leather strap; 
thick felt 6in. Xljin.; thin coloured felt 1ft. 6in. x 
6in.; solder; connecting wire. 



At this stage it may be as well to explain the type 
of soldering tags used by the author. Phosphor bronze 
draught excluder strip (Woolworths) is cut off into 
6in. lengths— old scissors will do for this— then cut 
into strips ^rin. wide. Try out with a scrap piece of 
paxolin. Drill a Uin. hole and thread one of the 
strips through until it jams tight. Bend each end 
down flat outwards. Place a small straight edge on 



172 



Panel size 10 x 3 /a, , material i^g thick paxolin 




To V1b switch on 
plate contact board 



To master switch 
common + 



To top. C tag 
on resistance strip 



Fig. 3: Circuit board layout for the vibrato oscillator and note generator. All components are mounted on the reverse side, to the wiring. 



slfe 



TO 

loudspeaker 



the strip over the hole 

Jin. from the bend, and 

with a sharp penknife 

score across the metal, 

still holding the straight 

edge firmly down, bend 

the strip up and down a 

few times until the metal 

breaks, leaving a \m. tag. 

The same is done at the 

back of the panel. Tags 

will be mostly used on 

the edges of panels, in 

this case drill the hole so 

that there is a space iin. 

left between the hole and 

the edge, bend outwards 

as before, this time using 

the panel as a straight 

edge, score and bend until 

the metal breaks clean in 

line with the panel edge. 

Deal with the other side 

as before. To use up strips 

which are slightly narrow, 

drill with a size smaller 

drill. With wider strip 

these are helped through 

the hole by using a wire 

file removed from its frame, broken pieces are ideal 

for this. File slightly each side where the strip will be 

inserted. These tags take solder delightfully easy, and 

with practice can be fixed quicker than ordinary tags. 

If desired the constructor can use the latter where 

indicated. 

The contact plates are | X l|in. each and we 
require 37. First experiments were made with alumin- 
ium, but proved too soft. Bright polished copper 
was an improvement, but stainless steel was finally 
chosen, because it can be conveniently obtained in 
6 foot lengths at the required |in. width (cost about 
12s.) one length being sufficient. We only need to 
take care in cutting off l|in. lengths, dead square. 
With a fine file clean off sawcuts, slightly radius the 
four corners, and slightly round the edges on the 



^ 16 Paxolin panel 



To master switch 
common + 




From output of 
generator panel 

ion control 



Fig. 4: Circuit board details of the pre- amplifier and output stage. 



polished side. When finished, stack together and with 
the edges on the flat surface of a board see that they 
are reasonably square, none unduly proud. Remem- 
ber that with 37 saw cuts something like 2iin, will 
be wasted, however there should still be several 
inches left if needed. Contrary to expectations the 
metal is not unduly hard to work. With the polished 
sides down, the plates should be laid down on a 
flat surface and protected with some newspaper. On 
the back of each plate mark two pencil lines diagon- 
ally from opposite corners, at the intersection, make 
a punch mark for drilling the centre hole to take the 
6BA screws. After drilling, to cleanly finish the holes 
on the polished side use a countersunk bit or larger 

— continued on page 192 



173 




It seems that each year the Fi goes Hi-gher and Hi- 
gher, unfortunately so does the price! A criticism of 
audio enthusiasts was given by one cynic who defined 
them as "People who listen to the equipment and not the 
music". After a day at the Hotel Russell listening to a 
great number of both units and music the following 
items of interest were noted. 



TUNERS AND AMPLIFIERS 

Richard Allen displayed their Class A Stereophonic 
Amplifiers. These amplifiers use transistors in Class A 
and Richard Allen offer some pretty convincing litera- 
ture that this is the way to real solid state hi-fi. Also on 
show, the C41 control unit. As shown in the photograph, 
this is quite a sophisticated unit. 

Braun have preserved their see-through covers, their 
new Audio 250 stereo control unit being no exception. It 
is equipped with a PS410 turntable, tuner which in- 
corporates a stereo decoder, and an amplifier section. 
The improved pick-up arm is fitted with a vernier scale 
for correct stylus pressure adjustment and is equipped 
with a M75-6 cartridge. The player has a fine speed 
control and a semi-automatic cueing device. There is 
also a tuner section for the reception of f.m., f.m. 
stereo, s.w., m.w., and l.w. broadcasts. Power output is 
given as 2 x 15 watts continuous rating with a fre- 
quency response of 30-30kc/s ± 0-5dB. Distortion 
below 0*5 % at 2 x 12 watts is claimed. If you want one 
it'll cost you £284 17s. 4d. 

Leak, a big name in hi-fi, showed "big brother" to 
their Stereo 30. The new Stereo 70 is all solid state and 
makers give the output as 35 watts per channel (both 
channels sine wave driven), total harmonic distortion 
0-1 % for all power levels up to 25 watts r.m.s,, response 
flat ± ldB 30-20kc/s. 

Philips offered an attractive system costing about £67 
and consisting of a GA228 record player, a GH925 
stereo amplifier providing six watts per channel, plus 
two GL559 speaker enclosures ideal for shelf mounting 
as they stand less than a foot high. 

Quad too are boasting all transistor circuitry. Their 
Quad 33 control unit and 303 power amplifier were on 
show, the latter rated at 45 watts. Also on show, the 
Quad FM Stereo Tuner covering 87-5-108Mc/s. 

J. Richardson Electronics Ltd. appeared for the first 
time at the Fair with their MAI 35 and MA 200 giving 35 
watts and 100 watts respectively for 0-25 % distortion at 
lkc/s in each case. These are valve amplifiers as is the 
SA170 stereo amplifier which has the same quoted 
figures per channel as the other two. Frequency response 
± 0-5dB 20-20kc/s. 

Sansui showed four new units at the Fair. One, their 
3000A stereo tuner/amplifier, might accurately be 



described as the most beautifully styled audio bomb 1 
have ever seen. Don't be taken in by the total harmonic 
distortion factor of less than 0-8% nor the ± l-5dB 
response from 10-50kc/s. Neither should the 53 trans- 
istors and 46 diodes fool you. If you get one you will 
have a complete hi-fi set-up which will give a total of 
1 30 watts. If this is too much, then try the A U777 giving 
only 70 watts total with a total harmonic distortion 
factor of 01% and ± ldB from 20-100kc/s. Prices 
167gns. and l05gns. respectively. 

TAPE RECORDERS AND DECKS 

Last year in our Audio Fair report, we mentioned 
that possibly the most noticeable trend was towards the 
use of cassette loading machines. This year however 
there were not many of these units around and the ac- 
cent seemed to be on the big, high-quality machines 
("high quality" varies from maker to maker quite 
noticeably this year). It is also interesting tonotethat the 
British manufacturers were outnumbered by overseas 
competitors in the tape recorder market, with Akai, 
Ampex, Oki, Sennheiser, Tandberg, featuring strongly. 

Akai exhibited their four-track stereo tape deck 
model 3000D which utilises silicon transistor preamps, 
three head system and grained wood finish. The price is 
£105 lis. 4d. Also on the stand were tape deck model 
X-150D — a cross-field stereo silicon transistor preamp 
type with four-track stereo/mono recording and play- 
back at £130 2s. 4d., and the M9 stereo tape recorder — 
a replacement for the company's M8 at the price of 
£195 3s. 5d. 

Model 753 stereo four-track tape deck was shown on 
the Ampex stand as the firm's lowest priced recorder at 
91gns. and Brenell introduced their Mark 510 series 3 
deck accommodating tape reels up to 10 Jin. diameter. 
Bosch (Uher) were showing their Royal De-luxe stereo 
tape recorder with two- and four-track facilities and 
2 x 10W power output. 

It was pleasant to see that Ferrograph have introduced 
a completely new generation of tape decks — the Series 7 
—which, the makers say, is a completely new design and 
incorporates features that a market survey showed 
users desired. This new unit is an all-silicon solid state 
model with field effect transistors used in the input 
stages. It can be vertically or horizontally mounted 
(this could be another trend) and unit construction pro- 
vides for the mounting of three individual units — the 
amplifier complex, power supply unit and the actual 
deck itself. These are mounted on a separate frame 
which is easily removable from the cabinet. Three 
motors are used — no belt or pulleys to go wrong- 
there are three tape speeds, variable speed spooling, 

— continued on page 212 



174 




A~Garrard SL95: B-Phiiips GH925: C-Richard Allen Class A Stereo: D-BSR UA75: E-Sansu! 3000A: F-Bosch (Uher) 
Royal De-luxe: G-Ferrograph Series Seven: H-EMI Speaker Set Model "750": l-Philips PR012: J-Sansui AU777 



175 



THE 




J.THORNTON-LAWRENCE 



GW3JGA 



continued from the June issue 



THE Clubman Mk VI is a Car Radio version of 
the Mk IV, but the a.f. power output stage is 
housed in a separate small box, which may 
either be attached to the back of the receiver or 
mounted separately. 

The Clubman Mk VI is connected to its output 
stage box by a multiway cable. This cable terminates, 
at the receiver, in a B9A plug which connects with 
a corresponding B9A valveholder socket (SKI) on the 
receiver back panel. See Fig. 39. The box may be 
disconnected at any time by removing the plug. A 
link plug may then be inserted into the socket to 
restore the receiver to normal operation from its in- 
ternal 9 volt battery. The "box" requires a 12 volt 
d.c. supply from the car battery (which must have 
positive earth) and provides approximately 2 watts 
a.f. output to a 3 ohm loudspeaker. 

■MkE & Mkm *4« Mk 




Circuit Description 



The circuit diagram is shown in Fig. 38. The 
12 volt negative supply enters the box via the fuse, 
Fl, and the terminal block. This supply then passes 
to the receiver through SKI pin 2 and then to the 
on-off switch SI. This slide switch is a double pole 
type, of which one pole is already being used for the 
9 volt internal battery supply. For the sake of 
clarity, this pole will be referred to as SI a. See Fig. 
40. The remaining unused pole Sib is now used for 
the 12 volt supply, the input being connected from 
SKI pin 2 to Sib tag 1. The 12 volt supply is returned 
to the box from Sib tag 2 to SKI pin 3. The 12 volt 
negative supply provides current for the output 
stage transistors TrlO and Trll, and for the receiver. 

A 9 volt supply is required for the receiver circuits 
*4- 




Fig. 38: Clubman Mk VI output stage, showing connections to 
Mk It, III and IV versions. 



SKI^^LT 



SKI B9A Valveholder 

PL1 S9A Plug 

PL2 B9A Plug (for link plug) 



PL2 



176 



and this is provided by the voltage dropping resistor 
R32 and the zener diode D4. The zener diode 
regulates the 9 volt supply so that correct operation 
of the receiver is achieved over the normal variation 
of input voltages expected from a car battery system. 
The regulated 9 volt negative supply is taken to the 
receiver via SKI pin 4 to the on-off switch Sla tag 2. 
The connection from the negative terminal of the 
9 volt internal battery is now taken to SKI pin 5. 
When the box is disconnected, a link plug, having 
pins 4 and 5 joined, may be inserted, thus restoring 
the 9 volt negative supply from the internal battery 




&^7 \^. 



To Receiver — 9Vline 



Phone jack 



Bl to the receiver 9 volt negative line. 

The output stage in the box consists of transistors 
TrlO and Trll connected as a Darlington pair and 
operating in class A. The input to TrlO is taken from 
the headphone closed-circuit jack socket Jl, via 
SKI pin 7. With the headphone jack plug removed 
a.f. signals from Tr3 collector are passed to TrlO 
base via CIO. TrlO operates as an emitter follower, 
in that amplified a.f current signals are fed directly 
to Trll base. The combined collector currents of 
TrlO and Trll pass through the primary of the out- 
put transformer T2. Amplified a.f. signal currents 
are passed through T2 
to the external loud- 
speaker. 

D.C. biasing of the 
TrlO and Trll is pro- 
vided by the potential 
divider R33 and R34, the 
emitter stabilising resistor, 
for the pair, is R36. Two 
forms of negative feed- 
back are incorporated in 
the output stage to im- 
prove the quality of repro- 
duction. Negative series 



Fig. 40 (above left): Rear of front panel, showing connections 
to S1a, b and J J, 



€ 



3^' 




Fig. 39 (below): Rear panel showing position of SK1 and 
power output stage. 



— iV-H SKlT 



"S^dia.- 



te"H- 



„ I /& dia, 



holes 



C © L 



Mounting position 
O for 

Power output stage 



y. 



Id | 

! 



1V4 



VS. 



9 4i 



f 



2V16 



l3/4 






p 2P\ 

i T2 I f-J 



Si 



r 



WiM^M 






3" 



Fig. 41: Metalwork comprising chassis and cover for the power 
output stage. Material 18 s.w.g. aluminium. 



t 



Ul^i i 



i_L 



9V4" 




DRILLING 
a — \in. dia. b — Utk dia. 
c — %in. dia. d — fain. dia. 



177 



current feedback is pro- 
vided by omitting the 
usual by-pass capacitor 
across R36, in this way 
the output signal current 
develops a signal voltage 
across R36 and this volt- 
age is in phase and in 
series with the input sig- 
nal. Negative shunt volt- 
age feedback is provided 
by connecting R33 to the 
collectors of TrlO and 
Trll. The a.f. voltage 
across the primary of T2 
produces an a.f. current 
through R33 and this is 
out of phase and in shunt 
with the input signal. If 
the receiver is discon- 
nected from the box and 
the link plug inserted, a 
link from pin 7 to pin 6 

reconnects the a.f. signal from Jl to the base of 
Tr9 and restores the normal operation of the internal 
loudspeaker output stage. Internal connections to 
SKI are shown in Fig. 42. 

To J1 Live outftut j 
tag ^ 



IHHnHH^BK 




To"Fr9 base Club man m 
( no connection * 
Clubman n & M } 

To — Ve Of internal .„ 

9V battery 




ToS1a,tag2. _* 

To S1b,tag 2 -* , 

ToS1b,tag1 < 

Fig. 42 (above): SK1 (B9A vaiveholder) viewed at tags. 
Fig. 43 (below): Internal wiring of power output stage. 



Car radio type 
fusenolder f 



3 -way 
tag strip 




(pin 3-* 
-2-* 



View of receiver and power output stage (not mounted on rear panel). 

Construction 

The complete a.f. power output stage and zener 
diode regulator are housed in an aluminium box, 
the construction of this is shown in Fig. 41. The box 
is made from 18 s.w.g. sheet aluminium. Providing 
usual care is taken with the bending no difficulties 
should be encountered. The chassis part of the box 
should be made first and the cover made afterwards 
so that a good fit can be obtained. If the chassis is 
printed 'in the flat", before bending, it is recommen- 
ded that the cover fixing screw holes "d" should be 
left undrilled. When the complete box is assembled, 
the actual position of these holes can be marked 
through the holes in the cover and then drilled. The 
cover is held on with two 4BA self-threading screws 
fitted in these holes. The output transistor Trll 
(OC35) is mounted in the position shown using a 
mica washer and insulated fixing bushes. An ex- 
cellent illustration of the method of mounting is 
shown on page 25 of the May 1968 issue of Practi- 
cal Wireless. Before fixing the transistor great 
care should be taken to ensure that no swarf or 
burrs are present on the chassis as this may punc- 
ture the mica washer when the whole assembly is 
tightened up. The driver transistor TrlO is mounted 
as shown in Fig. 43. The multiway cable is made 
up by twisting together the requisite number of 
different coloured stranded insulated wires. Screen- 
ing of the cable was not found to be necessary. 



Installation 

The completed box may be mounted on the 
rear panel of the receiver using two self-threading 
screws, as shown in Fig. 39. Alternatively the box 
may be fixed to the car in some more convenient 
place. The interior of the engine compartment should 
be avoided because of the possible high temperature. 

The standard type of car radio aerial will pro- 
vide reasonable results for general listening. The 
inner of the coaxial cable should be connected 
to the aerial terminal and the outer to the earth 
terminal, For the very best possible performance 
over a narrow band it is desirable to use a loaded 
whip aerial resonant at the desired frequency. 



tag strip 



178 



DON'T MISS THIS! 



; HAVE YOU GOT YOUR LASKY'S 

■i i CDCC Second Great Reprint Issue Now Beadj. 

1 1 r ™ ■■ c Jtast send your name, address and 1/- for post only 



CATALOGUE ii 

n 




CONSTRUCTORS BARGAINS 



SINCLAIR SPECIAL 

THE MICRO FM 

THE WORLD'S ONLY COMBINED 
FM TUNER AND POCKET RECEIVER 

A unique 7 traaifHtorFMauperhettiuiKr-retfilverfor 
(xuistruetorfl, which, ruqiiires no alignment whon built 
and which ua^s pul«e ounitliig Lletectlon for better 
quality. Can bo used aa a tuner for ampiitlep, tape- 
recorder, Btfiwg or as a self-contained picket FM 
receiver contained with battery in a cause no bigger 
than a packet »f ten cigarettes! The Micro FM is 
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dial, in keeping with Ita outstanding pyrlormaTice, 
Technical spec: 7 transistor. £ diode superhet FM 
with one output to amp., or tape-recorder and one 
which enables act to be usea as a self-contained 
pocket FM. receiver- Low IF* Pulse counting dis- 
criminator. Telescopic aerial. Audio rcsponpe: 10 to 
*20 T 00Oc,'s -± IdB. Signal to noise ratio : 36dB nt SQriiV, Sensitivity 
Typically a micro volts. Power sonree; Standard 9 volt battery. 
Size 2 15/10 x 1 11/16 x Jin. T plus aerial. 

LASKY'S PRICE £5.19.6 in kit form. p os t2/e 



THE Z-12 INTEGRATED 12 WATT AMP AND 
PRE- AMPLIFIER 

EightspeeialH.F. Traimi&tGra are usod in I In.- i-ri.ruii'kab3e integrated twr Ivy watt amplifier* 
Outstanding features are its great veraatitlty, t:ompat!.tnes& t power and brilliant perform- 
ance. The Z*Vi Is equally suitable for use as a true Hi-Fi amplifier, In an electric guitar, 
aa a P.A, unit ior car radio or in an intercom system. The inputs can be matched to ail 
pick ups, mkniphonei and radio tuners and detailed circuits for appropriate tone and 
volume controlfl arc given in the manual supplied with every Z-12. Technical specification: 
Oaiput: C|ag& JJ* ultra linear, with generous negative feed-back. Output: 12 watts K.4L.3. 
Arabic power (30 watte peak). Frequency response i 15 to 50,000 c/» r- ldB. Input sensi- 
tivity: 2m V into 2K ohms. Signal to noise ratio: better than fiOdB. Output impedance: 
suitable for 3, 7- & and 15 ohms speakers. (Two 3 ohms speakers mav be used in parallel.} 
Powerr equipments : $ to *2Q volte 0.C. or Sinclair PZ»4 mains power supply unit which is 
available at 8978 extra. Size 3 x 1 J x l|ln. Weight 3 ozs. 

LASKY'S PRICE 89/6 fully built. Posts/- 
STEREO 25 

DE LUXE STEREO 
PRE-AMP AND 
CONTROL UNIT 

A first class pre -amp and tone 
control unit is vital to the per- 
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particularly where a modern 
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used. The Sinclair Stereo 25 has 
been designed tn match the excellent characteristics of the Z.12 Controls: Bass lift/cut, 
treble lift/cut, vnluine, balance and Input selection. Supplied ready built with full Installa- 
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power supply unit. Sensitivity: for 10 watts into 1-5 ohm load per channel. Mic* 2mV into 
50 K ohms. Pick up: 3m V in 50 K ohms. Radio: 20 mV into 10 K ohms. Frequency res- 
ponse: (Mic and Radiu) 20 c/s to 30 Kc/s ± ldB to 100 Kc/s ± 3dB. KIAA equalisation 
for pick up. &l£c G 1 x 2 J- x 2£Lra, 

LASKY'S PRICE £9.1 9.6 fully built, post 3/e 



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Branches \ ' 

207 EDGWARE ROAD, LONDON. W.2 TeL 01-723 3271 

Open all day Saturday, early closing 1 p.m. Thursday 

33 TOTTENHAM CT. RD., LONDON, W.1 TeL; 01-636 2605 




Open all day, 9 a.m. — 6 p.m. Monday 10 Saturday t .,-, rnnimnr nn . n . ».._»., 

152/3 FLEET STREET, LONDON, E.C.4 TeL: FLEet St. 2833 " 8 ED ™A R E ROAD LONDON, W.2 TeL: 01-723 9789 

_ , , . _ , , . ■ c . -i ° Den a " da V Saturday, early dos«nq 1 p.m. Thursday 

Open all day Thursday, early closing 1 p.m. Saturday 

ALL MAIL ORDERS AND CORRESPONDENCE TO: 3-15 CAVELL ST., TOWER HAMLETS, LONDON, E.l TeL: 01-790 4821 



SPECIAL INTEREST ITEMS 



TRIO Model TK-60BE 

TRANSISTORISED AM/FM MULTIPLEX 
STEREO TUNER AMPLIFIER 




AT A PRICE YOU CAN AFFORD! 

The 36" Transistor TRlOTK-GOBEineorporatessuperb modern styling with many features 
normally found in mode]* costing fiMfa more. Tins great value {or money Hi-Fi unit oilers 
the lollowiug superb features : Tuner AH/PA 4-gung tuning condenser all tratwistor front 
«nd provides FM 2>5mY fieiiHitlvity* *Autoraatle I'M/Stereo Mono mode silent switching 
circuit with Stereo signal beacon. 'Illuminated pinpoint AM/FM tuning meter, *4 diode 
time division multiplexer de-coder giving StftLB cbttitud aeparation. Amplifier. *AI1 silicon 
transistor amplifier provides wide 20 — 50,000 Hi frequency response. "Exclusive blow-out 
iree automatic circuit breaker tor power transistor protection. *3peaker output terminals 
and power for 2 sets of stereo speakers — switch selected {A speakers, 5 speakers, A-rE 
speaker?, head phone*), •Centre channel output, p Full range of controls. *Front panel 
stereo phone jack, *Dlreet tape monitor switch for tape monitoring without changing 
■cable connections. *D1N connector for tape recorder. Brief spec.: Amplifier— Music Power 
00 watts (IMF standard 4 ohmij), Continuous power — 20 watts per channel. Signal to noise 
ratio— Phono tfOdB, Tape Hl>-60dB. Input sensitivity— Phono 2mV t Tape HD-*2-5mV% 
AL'X. 150mY» Tape play 150mV, Speaker Impedance— 4/16 ohms. Controls : Input selector, 
Mode, HP and LF ft I torn, separate treble and bass controls for each channel, balance, 
loudness tape monitoring, output selector. Tuner i FM cover 88-10& Mc/s, AM cover 
MO-1600 Kc/s. FM Uaniinnic Uistnrt-ion— 0*e%. FM Signal to Noise Ratio— 60d». FM 
Selectivity — 40dR. General! For 110/250 V mains. Finish — brushed aluminium with ham- 
mer enamel case. Size 17* x B\ x 14Ln. 

LASKY'S PRICE 69 GnS. Carriage FREE in U.K. 

LASKY'S CLEAR PLASTIC 

PANEL METERS 

Precision made in Japan by HIOKI. Each meter boxed and 
lully guaranteed witli nil axing nnta and washers, ab.ua are 
of Itont panel . Add 1 /fl P. on each. {Quotes for quantities.) 
Type KR-52 3 x 2iin. (itlustrated). 

1mA DC 47/6 lOOuA 47/8 

5mADO 38/e 600(iA ,..87f6 



30DVDC 38/6 lmASMeter. 

fiOLtA 66/- 

Type 3HK-38A l.'in. ;i|i:;in- 

1mA DC 89/6 

6mA DC SZ/6 

300V DC .22/6 

SOfiA .38/- 

lOOiiA 29/6 

OOOHA 87/6 

BiiiA 8 meter , , 89/6 

True MK-45A 2in. aquaro 

6mA DC BS/- 

8mA DC 25/- 

300V DC 25/- 

500|XA 85/- 

1mA 9 meter 35/- 



.39/8 




Type KH-65 3ix3in. 

ImADO 86, 

SraADO 36, 

300V DO SB, 

SOixA 58, 

lOOLtA : 

OOOttA 42^ 

1mA 8 meter , 39 

Type MK-06A Sin. square 

1 raA DC 33, 

Cm A DC 36, 

300V DO , 

fiOOtAA 39i 

1mA 8 meter 37, 



NEW INTERNATIONAL TAPE 

FAMOUS AMERICAN MADE BRAND TAPE AT RECORD LOW PRICES 



3iu. Message tape, ISOlt 8 6 

3fn. Message tape, 325ft. 3 

31n. Mfieeaga tope, BOOK 7 8 

3iin. Triple play, uOOit,, Mylar , . 10 
4lii. Triple piav, MOOlt, Mviar . . 17 S 
Sin, Double play, l!>00ft. Mylar 15 
Sin. Long play, 900ft, Acsetate , , 10 
5in. Standard play, BOO/t.PV'C. . 3 6 
Bin. Triple play. I'gOOft.Mvlar. .. 36 
6 J in. Double play, 1 S00 It. Mylar 22 8 
3 jiu. Long play, 1300ft. Auetate 18 6 



5 Jin. Standard play, SfiOlt. PVC 11 6 
5jln. Long piny, 1200ft. Mylar . , 15 
5|ln. Triple play, 2400It. Mylar. . 45 
Tin. Standard play, 1300ft. Ace- 

7 la . Standard 'play, ' iiOO " ft'. My 

lar , 

71n. Long play, 1800ft. Mylar 
Tin. Duuble play, 3400lt. Mylar £6 6 
Tin. Long play, 1800ft. Acetate , 15 
7Io, Triple play, 3600ft. Mylar. . 50 



12 6 



12 8 

19 6 



F. 4 P, II- extra per reel. 4 reels and over Post Free. 



42 TOTTENHAM CT. RD., LOKCQM. W.1 

Open all dav Thursday, early closing 1 p.m. Si 



Tel.: 01-580 2573 



179 



BATTERY RECORD DECKS 

E speed mode] 33 1/3 and 45 r.p.m , 8v. operated. Complete 
With piok-up fitted crystal cartridge. Plays 7, 10, IBin. 
records. Fitted auto, stop and start. Idea) for use with mini- 
ature transistor amplifiers. POST 
OUR PRICE CQ/C 2/6 
4 speed Model 9 volt. 10/- eitra. J3 / u 

LIMITED QOAKTITY ONLY— EXPORT MODELS. 

POCKET MOTOTO- COIL MULTIMETER. 
0-l,000v. A.C./D.C, ohms to 100k. etc., 
SUPERIOR MOVING COIL MULTIMETER 
0-2,600y. D.C. 20,000 ohms per volt, 0-l,000v. A.C. 
Ohm i to 6 meg. SO Micro am ti (Fall list Meters S.A.E.':. 

NEW MULLARD TRANSISTORS 6/- each 

0C71, 0072, OC81, OG44, OC45, OC171, OC170, AF117 

REPANC0 TRANSISTOR TRANSFORMERS 
TT45. Push Pull Drive. fl:l CT, 6/-. TT48. Output. CT 8:1, 8/-. 
TT49. Interstage etc. 4. 5:15/- TT52 Output 3 ohms, 20- 15/- 
TRANSISTOR MAIKS ELIMINATORS. FAMOUS MAKE 
FULLY SMOOTHED. FULL WAVE CIRCUIT /I Q /C 
9 VOLT 600mA Size Si8|i 2in. ** : '/ D 

DITTO TRANSFORMER ONLY. Size ZjiHii; .. IQ/6 

WEYRAD P50 — TRANSISTOR COILS 



49/6 

99/6 



RA2W 6 in. Fertile Aerial 
with ear aerial coil , 12 /B 

Ose. P50/1AC 6/4 

LF, P60/2CC 470 ko/a . . 6/7 
3rd LF. P50/3CC 6/- 



Spare Cares Sd, 

Driver Tram. LFDT4 . . 9/8 
Printed Circuit. PCA1 . . 9/8 

J.B. TnniuK Gang 10/8 

Wsvrad Booklet 8/- 



Teleseopic Chrome Aerials fan, eiteada to 23in. 5/-. 

I 80 0nm Coax 8 D ra . 

SEMI-AIR SPACED 40 yd. 
20/-; 80 *d. 30/-, FRINGE 
LOW LOSS. Ideal 



VOLUME CONTROLS 
Long spindles. Midget Size 
6 K. ohms to 2 Mee. LOO or 
LIN, L/8 3/-, D.P. 5/- 
STESEO L/S 10/6. D.P. 14/6 
6K. S_P. Edge type, 5/-. 



S25 lines yd. 



1/6 



COAXIAL PLUG 1/3. PANEL SOCKETS 1/3, LINE SOCK- 
ETS 2/-. OUTLET BOXES. SURFACE OR FLUSH 4/6. 
BALANCED TWIN FEEDERS 1/- yd. SO or 300 ohms. 
CAR AERIAL PLUGS 1 /B ; SOCKETS 1/3 : LINE SOCKET 2/- . 

SELCOL 

GUITAR PRACTICE 
AMPLIFIER 

ONE WATT OUTPUT 

Portable cabinet 12 i 4 i 

Bin,, all transistor, fitted 

7 7- 4in. speaker. Volume 

control. Jack socket. Uses 

PP9 battery. 7Q /fi Post 6/6. 

OUR PRICE »■/■ Worth double, 

RETURN OF POST DESPA TCH 




MAINS TRANSFORMERS ™* 

250-0-250 80mA. 8.3 v. 3.5 a, 6.3 v. 1 a, or 5 v. 2 a. 30/- 
360- O-360-8U mA. 8.3 v, 3.5 a, 3.3 v. 1 a, or 6 v, 2a 86/- 
300-0-300?. 120m A „ 6.3 v. 4 a, C.T.; 8.3 v. 8a ., 46/- 

MINIATURE 200 v. 80 mA., 8.3 v. 1 a 12/6 

MIDGET 220 v. 45 mA.. 6.3 v, 2 a. 17/8 

SMALL 250-0-250 50 mA. 6.3 V. B a 19/8 

HEATER TRANS. 8.3 v. 1J a., 8/6; 6.3 v. 4a 18/8 

Ditto tapped sec. 1.4 v., 2. 3. 4. 5. 8.3 v, 1' amp. . , 12/6 
GENERAL PURPOSE LOW VOLTAGE, Outputs 8, 4, fi, 

6, 8. 9. 10, 12, IS. 18. 84 and 30 v. at 2 a 30/- 

1 amp., 6. 8. 10. 12. 18, 18, 20, 24, 30, 36, 40, 43, SO 35/ 
AUTO TRANSFORMERS 0-115-830 v. Input/Output. 
60w. 18/8: l»0w. 30/-: 500w. 92/6: lOOOw. 175/-. 

CRYSTAL MIKK INSERTS 

U ■ Sin. 6/6; ACOS slxMo. 3/8; BH3 liu. dia. B/6 

MOVING COIL MIKE with Remote Control Switch, .19/6 

AlA, VUKPOKl-I HKAI>l>H(»Ni:S 

H.R. HEADPHONES 2000 ohms 19/8 

H.H. HEADPHONES 2000 ohms Super Quality . . 35/- 

LO W RESISTANCE HEADPHONES. 3-:i n;:ni.< " 'i ' 

HEJslSTOHS. Preferred values, 10 ohms to 10 raec. 



r »/- 

< 2/- 
V 8/- 



i w„ ) w„ 1 w„ 80% 3d.; 11 w. 3d.; 8 w. 1/-; I w. 16% 8d. 
HIGH STABILITY. J w. 1% 10 ohms to 10 mee„ 2/-. 
Ditto 5%. Preferred values 10 ohms to 88 meg., fid. 
5 walt-i 0.5 to 8.8 ohm 3 w. 

10 watt }■ WIRE- WOUND RESISTORS 

15 watt J 10 ohms to 6.800 ohms 

10K, 15K, 80K, 26K, 68K, 10W, 3/- 

8PEAKER FRET Tyuau various colours, 52in. wide, trom 

10/- It.: B8iu. wide Irom 5/- It. SAMPLES S.A.E. 

EXPANDED METAL Gold or Silver 18 * 18in. 6/-. 

VER080ARD 0.15 MATRIX 

81 >=5tn. 3/8d. 2j ■ SJin. 5/2d. 3 J x Slln. 8/84. 

EDGE CONNECTORS 18 way 5/-; 84 way 7/8. 

PINS 36 per packet 3/4d. FACE CUTTERS 7/6d. 

S.R.B.P. BOARD 0.1S MATRIX 2 sin. wide 6d. per lin.: 

3^in. wide 9d. per lin. ; Sin. wide 1/- per lin. (up to 17 In.]. 

BLANK ALUMINIUM CHASSIS. 18 s.w.g. 851n. sides. 

7x4in., 5/8; 9x7in.. 6/6: 11 r. 3iu„ 8/6; llx7in„ 7/8; 

18*9in„ 9/8; 14 -llin., 12/8; 15 '< 141n., 15/-. 

ALUMINIUM PANELS 18 s.w.r. 12 * 12in., 6/6; 14 x fitn.. 

5/8; 12 >: Sin.. 4 6; 10 ■ Tin., 3/8:8 6in..a/0:6> 4in.. 1/fl. 

THE INSTANT 

BULK TAPE 

ERASER AND 

RECORDING 

HEAD 

DEMAGNETISE!? 

200/250V. A.C. Leaflet S.A.E. 




Post iff, ' 



ALL EAGLE PRODUCTS 
EAGLE AM TUNER. Med Wave. Transistor TO /fi 
Superhet. Fcrrito Aerial etc / 3/ U 



EAGLE DE LUXE TAPE SPLICER. Cuts, trims 
joins lor editing and repairs. With 3 blades. 



17/6 



EAGLE 4 CHANNEL TRANSISTOR MIXER. Add 
musical niuhlichts and sound effects to recordings. Will 
mi* Microphone, records, tape and tuner with 
separate controls into single output. 



59/6 



TRANSISTOR FM-LW-MW TUNER. 10 semi conductors. 
Calibrated tuning dial. 9 v. operation, FM88-108 Mo/«; 
MW 180-560 metres. LW 860-2000 tnelres. F1/I/1Q/R 
Size 2| i 8 x 5Jin. LI**/ I 3/ D 



EAGLE 3 WATT AMPLIFIER, 4 Transistor 
Pusb-Full Ready built, with volume control. 



69/6 

40PAGE CABLE CATALOGUE Si- POST FREE 



■*• RADIO BOOKS • [ Postage 9d.) 

High Fidelity Speaker Enclosures and Plans 8/- 

Trausiitor Superhet Commercial Receiver! 7/8 

Mullard Audio Amplifier Manual 8/8 

Radio Valve Guide. Booki 1, 2, 3 or 5 5/- each 

Practical Radio Inside Out .4/8 

Transistor Audio Amplifier Manual Book 1, 3/8, Book 2, 8/- 

Shorlwave Transistor Receivers 6/- 

Transistor Communication Sets . , 6/- 

International Radio Station) List 8/6 

Modern Transistor Circuits lor Beginners .7/6 

Sub-Miniature Transistor Receivers 5/- 

Wireless World Radio Valva Data 9/6 

At a glance valve equivalents 6/- 

Valves. Transistors. Diodes equivalent Manual 10/6 



WIRE-WOUND 3-WATT 
POTS. T.V. Type. Values 
10 ohms to 30 K , 
Carbon 30 K to 8 
meg. 



4/6 



WIRE-WOUND 4-WATT 
STANDARD SIZE POTS. 
LONG SPINDLE 
VALUES 50 OHMS 7 /fi 
to 100 K, ' I" 



VALVE HOLDERS, MOULDED 9d.: CERAMICS 1/- EACH. 

SANGAMO 3 inch SCALE METERS 45/- ea. 
Various calibrations and movements. 100 Microamp; 
1 Milliamp; 50-0-50 Microamp, etc. S.A.E. lor list. 

BRAND NEW QUALITY 
EXTENSION LOUDSPEAKER 

Cream plastic cabinet. 80ft. lead and 
adaptors. For any radio, intercom, tape 
recorder, etc. 3 to 15 ohm. POST on / 
Siie:7r*5r*S-. g/B du / 




Minimum Post and Packing charge 2/6. C.O.D. Si- extra. Full list 11-. 



CALLERS WELCOME 



RADIO COMPONENT SPECIALISTS 337 whitehorse road, west croydon 

Written guarantee with every purchase. (Ei/iori— send remittance and etira postage, no C.O.OJ Buses 133, 68 pass door, S.R, Sin. Selhurst. To I, 01-884-186$ 



MARTIN 

IS HIGH FIDELITY 
plus 



ADD-ON-ABILITY 
THRILLING POWER 
DEPENDABILITY 
GENUINE ECONOMY 



How would you like to start with 
a simple amplifier, say, and add to 
it until it became a fully stereo 
twenty watt amplifier with FM 
tuner and facilities to take the most 
sensitive low output pickups ever 
made? With Martin Audiokits 
it's easy, for with these superbly 
engineered all -transistor prefabri- 
cated units, success is built in from 
the start and you build to your own 
preferred plan. ITS A MONEY 
SAVING SCHEME, TOO. 



Details from: — • Trade enquiries invited. 

MARTIN ELECTRONICS LTD., 155 High St., Brentford, 
Middlesex. ISLeworth 11 61 



To MARTIN ELECTRONICS, IBS, High Street. Brentford, Middlesex. 

I have not had your leaflets before. Please send them on 

AMPLIFIERS □ FM TUNER Q RECORDAKITS Q 

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1 eCTC IB*. 1S9, 1TJ, 334, 3V4. DAF91, DF91, DK01, ULflii, DLS4. 
1 O E 1 O s e t o( 4 lor 17/6. DAFflB, DF98, DK96, DL06, 4 lor 86/-. 






OZ4 4/6 


10P13 IB/8 


DH77 4/- 


KF'Jl 3/8 


POLSS 8/3 


BQ094 7/1 




1ASOT 5/- 


12AT7 3/9 


DH81 12/8 


EF97 7/6 


FCI^S 8/6 


UCC85 6/8 


1A7GT 7/6 


12AU6 4/9 


DK32 7/9 


EF183 6/8 


PENA4 6/9 


UCFH0 8/3 


1H50T 7/8 


12AU7 4/9 


DK91 6/6 


EF184 6/8 


PEN36U16/- 


LCH42 9/9 


1NBGT 7/8 


12AX7 4/9 


DK82 9/3 


EH 90 6/6 


PFL200 13/- 


UCI181 8/6 


HW 5/6 


12K80T 7/8 


DK98 7/- 


EU3 8/8 


PU6 9/8 


i:CLS2 7/6 


184 4/6 


-«!'- 10/8 


DL33 6/8 


HJ.34 9/8 


PL81 7/8 


UCL83 9/3 


188 4/3 


'iOLl 18/9 


OL35 8/- 


EL41 9/6 


PL82 6/6 


UF41 9/fl 


1T4 2/9 


20P3 14/9 


DL02 G/9 


EL84 4/9 


PL83 7/- 


UF60 71- 


3A8 8/6 


20F4 18/6 


1)1.94 6/9 


F.LB0 6/- 


PL84 8/3 


OF«9 6/3 


394 5/9 


25U40T] 1/8 


mJe 71- 


EL9S 6/- 


PL500 13/- 


CI.41 9/6 


3V4 5/6 


SOC1 7/- 


DY8S 8/9 


EB80 6/8 


l-l.."- J 13/6 


UL44 80/- 


bU40 4/6 


30C1S 11/6 


DY87 5/9 


EMS1 6/8 


I'LrJi.i 15/- 


CTL34 6/8 


SV40 8/- 


30C17 12/8 


E A11CS 8/8 


EM84 6/3 


PX23 10/8 


UY41 71- 


6Y30T 5/9 


30C18 91- 


EAF42 8/6 


EM37 7/6 


PY32 16/- 


UYS5 5/8 


SZ4G 7/6 


30 FO 12/- 


EB91 2/3 


EY51 7/- 


PY33 10/- 


VP4B 10/6 


6/301,2 18/6 


30FL1 12/6 


EBC33 7/8 


EYS8 6/3 


PY80 8/8 


VF132181/- 


6ALS 8/3 


30FL14 12/8 


EBC41 81- 


K/i'i 7/6 


PY81 5/8 


Z77 3/6 


GAM6 3/6 


301,1 8/- 


EBF80 6/- 


EZil 7/8 


PY82 6/- 


Trans iston 


6AQ5 4/8 


30JU10 14/- 


EBF8B 8/8 


EZS0 4/8 


PY83 6/8 


AC107 3/6 


8AT8 41- 


301.17 13/- 


EC90 2/9 


F.Z61 4/9 


PY88 7/8 


AC 127 8/- 


6A1-6 S/S 


30P4 12/- 


BOOS 3/9 


KT.il 8/9 


PY800 6/8 


AB140 7/6 


UBA6 4/6 


30F12 11/- 


BCCS2 4/9 


KTS1 15/- 


PY801 6/9 


AF102 18/- 


6BM 4/3 


3UP13 12/- 


ECC83 71- 


STS 14/8 


K19 8/6 


AF116 3/- 


6B06O 15/- 


30PI-1 12/6 


ECGS4 8/8 


FC88 9/8 


K20 12/8 


AF118 3/- 


SltJii 6/9 


30FL13 14/8 


ECCBS 4/9 


peas 9/s 


TH21C 9/9 


AF117 8/8 


6F13 3/6 


30PL14 14/6 


F.CC804 18/8 


PC97 8/8 


I '-'a 13/- 


API 18 3/- 


6P14 8/- 


36L6GT 8/- 


ECF80 71- 


FC900 8/3 


U2B 11/8 


Ai*124 7/6 


6F23 18/6 


30 W 4 4/6 


ECFS2 6/8 


PCC84 6/- 


U47 13/8 


AF125 3/6 


6K70 8/6 


3SZ4QT 61- 


ECF86 9/- 


PCC89 10/8 


U49 13/6 


AI-M26 7/- 


6KSO 4/3 


85A2 7/3 


EOH3S 6/- 


POC189 9/9 


U52 4/8 


AF127 3/6 


0L18 6/- 


6083 12/8 


ECU42 10/8 


PCFS0 7/- 


U78 3/8 


O C 22 6/- 


CV0O 3/6 


ASS31 9/- 


K'Mi.si 5/9 


PCFS2 8/- 


Ij 191 11/- 


OC26 5/- 


6V8GT 8/6 


BSfi 4/9 


ECHS4 7/8 


PCFS6 8/9 


U301 18/6 


OC44 2/3 


6X4 3/6 


1)729 18/8 


ECD90 6/9 


PCF80011/6 


L'SOl 18/9 


OC45 8/3 


tiXSGT 5/8 


CCH30 10/- 


ECL62 8/9 


PCF801 7/3 


CABCM 6/3 


OC71 8/8 


7B8 10/8 


T>AC32 7/8 


Kl'llXi 8/3 


PCF802 9/6 


t"AF42 9/6 


OC72 8/8 


7B7 7/- 


DAF81 4/3 


EF39 3/8 


POF805 9/- 


UB41 6/6 


OC75 8/- 


7C3 18/- 


DAKU-i 6/- 


F.F41 9/6 


PRF80S11/6 


UBC41 7/9 


OCS1 8/3 


7CW 6/8 


DCC90 8/6 


F,F80 4/9 


l-r>/-;:.~ 12/6 


UBFM) B/- 


OC81D 2/3 


7H7 6/6 


I>F33 7/9 


Kl'^r, 5/6 


PCL82 7/8 


UBF8B 6/9 


OC82 8/3 


7Y4 8/6 


Hi'91 8/9 


KK-r. a/'J 


PCI,83 9/- 


UBL21 9/- 


OC82D 2/8 


10F1 16/- 


1>1'96 6/- 


EF89 8/3 


PCL84 7/8 


GC92 5/- 


OC170 2/8 


READERS RADIO 


85 TORQUAY GARDENS, REDBRIDGE, ILFORD, 


ESSEX. Tel. 01 -550 7441 


Foslage on 1 valve 9il. extra. On 2 valves or mure, postage 6d. per 


•valve eitra. Any .Parcel Insured against Damage In Transit 6d. estra. 



180 




MONTHLY NEWS FOR DX LISTENERS 



CD 

s ■§ 

0) 






THE BROADCAST BANDS by CHRISTOPHER DANPURE 



WITH the summer schedules now in the second 
month of operation and sunspots at their height 
of the 11 -year cycle everyone is happy. In last 
month's issue I devoted the column to propagation and 
clearing up transmission queries. This month I will 
reverse that and only give the propagation predictions 
in details for N.E. Asia, S.E. Asia, Australia via Asia 
and S. America North of Amazon, so here we go. 

Africa: Mornings and afternoons, 25 and 21Mc/s; 
evenings, 21, 17, 15 and HMc/s; night hours, 15, 11, 
9, 7 and 6Mc/s. 

N.E. Asia: 0400-1600, 17 and 15Mc/s; 1600-2200, 
17, 15 and HMc/s; 2200-2400, 15 and HMc/s; 2400- 
0400, 15Mc/sonly. 

S.E. Asia: 0800-1200, 21 and 17Mc/s; 1200-1400, 
21, 17 and 15Mc/s; 1400-1600, 21, 17, 15 and IlMc/s; 
1600-1800, 21, 17, 15, 11 and 9Mc/s; 1800-2000, 21, 
17, 15, 11, 9, 7 and 6Mc/s; 2000-2200, 17, 15, 11, 9, 7 
and 6Mc/s; 2200-2400, 17, 15, 1 1 and 9Mc/s; 2400-0200, 
17, 15 and IlMc/s; 0200-0600, 17 and 15Mc/s; 0600- 
0800, 21 and 17Mc/s. 

Australia via Asia: 1000-1200, 21 Mc/s only; 1200- 
1330, 17Mc/s only; 1330-1600, 15Mc/s; 1600-1800, 
IlMc/s; 1800-2100, 11, 9 and 7Mc/s; 2100-2200, 15, 11 
and 9 Mc/s; 2200-2400, 17, 15 and IlMc/s; 2400- 
0200, 17 and 15Mc/s; 0200-1000. This circuit is closed 
for Broadcast Bands. 

S. America (North of Amazon): 1200-2000, 2 1 Mc/s; 
2000-2200, 21, 17 and 15 Mc/s; 2200-2400, 21, 17, 15 
and 11 Mc/s; 2400-0200, 17, 15, 11 and 9Mc/s; 0200- 
0400, 17, 15 and 11 Mc/s; 0400-1000, 17 and 15Mc/s; 
1000-1200, 17Mc/s only. 

EUROPE 

Holland: R. Nederland will operate the following 
schedule for its weekday English programmes, 0730- 
0820 on 11,730, 9,715 and 9,525; 1430-1520 on 21,480, 
17,810 and 6,020; 1900-1950 on 11,730, 9,590 and 
6,020; 2000-2050 on 11,730 and 6,020; 2100-2150 on 
17,810 and 1 1,730; daily English relayed from Bonaire 
2130-2220 on 15,220 and 0130-0220 on 9,590; special 
English programme relays on Tuesdays and Fridays 
only 1430-1445 on 21,540; 1530-1545 on 21,570 and 
21,540; 1700-1715 on 21,570 and 21,540; 2035-2050 on 
21,540 and 17,810. Weekday English news relays to the 
West Indies 1652-1704 on 21,505 and 21,480; 1900-1912 
on 21,505 and 21,540; 2352-0004 on 17,750 and 11,945. 

Happy Station programmes from Hilversum on 
Sundays only 0600-0720 on 9,715 and 6,020; 0730-0850 
on 11,945 and 9,525; 1030-1150 on 11,730, 9,715 and 
6,020; 1430-1550 on 21,480, 17,810 and 6,020; 1600- 
1720 on 21,570 and 11,730 only; 1900-2020 on 15,425 
and 11,730; 2030-2150 on 21,540, 17,810 and 6,020; 
2200-2320 on 21,540, 15,320 and 6,020. Dutch by radio 
lessons in English on Sundays only 0530-0550 on 



11,730, 9,715, 9,525 and 6,020; 0730-0750 on 21,570, 
21,480 and 6,020; 0800-0820 on 21,570, 21,480 and 
6,020; 1600-1620 on 21,480, 17,810 and 6,020; 1700- 
1720 on 21,540, 21,505 and 6,020, the above schedule 
runs until September 1, 1968, 

Norway: R. Norway now operates as follows until 
September 1 on Sundays and Monday mornings the 
last 30 minutes is in English. 0700-0830 on 25,730, 
21,730, 17, 825, 17,755 and 15,175; 1100-1230 on 
25,730, 21,730, 17,825, 17,755 and 7,240; 1300-1430 on 
25,730, 21,730, 21,655 and 17,825; 1500-1630 on 
25,730, 21,730, 21,655, 17,825 and 15,175; 1700-1830 on 
25,730, 21,730, 21,655 and 17,825; 1900-2030 on 
25,730, 21,730, 21,655, 17,825 and 15,175; 2100-2230 
on 21,730, 21,655, 17,825 and 15,175; 2300-0030 on 
"21,730, 17,825, 15,345, 15,175 and 1,578; 0100-0230 on 
15,345, 11,850, 11,735 and 1578; 0300-0430 on 21,730, 
11,860, 11,850 and 11,735. 

Switzerland: The Swiss Shortwave Service now 
transmits: 0700-0800 (weekdays only) on 9,535, 6,165 
and 3,985 in English. Daily English transmissions now 
run: 0700-0800 on 11,775 and 9,590; 0845-0945 on 
21,520 and 17,830; 1000-1100 on 21,520, 17,855 and 
15,305; 1130-1230 on 11,865 and 9,665; 1315-1415 on 
21,520, 17,845 and 15,305; 1500-1600 on 21,540, 
17,830 and 15,305; 1815-1915 on 17,845 and 15,180; 
1930-2030 on 11,865 and 9,665; 0130-0230 on 15,305, 
11,715 and 9,535; 0445-0545 on 11,715 and 9,720. 

AFRICA 

Congo Democratic Republic: R. Congo, Kinshasa has 
been heard by M. Reed in Bournemouth, Hants on 
15,245 starting at 2230 until after 0400. 

South Africa: The All Night Internal Service of 
Radio South Africa is now on 3,250 and 2,376. 

ASIA 

Afghanistan: R. Kabul now transmits from 1730-1830 
in German and English on 15,265 and 11,770 to 
Europe. 

Cambodia: R. Pnom Penh has been heard with 
European Service on 17,710 from 0530-0800 but with 
extreme interference from Moscow also operating on 
17,710, also beams to Europe from 1730-1800 on 
15,255 but this is blotted out by R. Nigeria, Lagos, 
also on 15,255. 

Ceylon: R. Ceylon has a daily overseas transmission 
to Europe from 0700-0800 on 17,815 in English, it has 
also been heard irregularly on 21,525. 

India: AH India Radio transmits to the UK and W. 
Europe from 1745-1945 on 11,620 and 7,215; 1945- 
2030 on 11,620, 9,912 and 7,215; 2030-2230 on 9,912 
and 7,215. 

Indonesia : The Voice of Indonesia has been heard with 
its programme in English beamed to Europe from 1900- 
2000 on the new frequency of 1 5, 1 10. 



181 



THE AMATEUR BANDS by DAVID GIBSON, G3JDG 



QUITE a good month on the six amateur 
bands, but 10 metres has been a little dis- 
appointing. One would have thought that 
openings and propagation would have been more 
consistent, bearing in mind the help this latter band 
is (or should) be getting from the sun. 

The Pacific and S. America have been in frequent 
evidence on 20 metres and Oceana has featured 
prominently on 40 metres at times. The l.f. segments 
(160/80/40) have been rather more noisy than usual, 
while top band in particular has been an awful din, 
particularly after dark. 

S. Herod reckons "peak" DX times are early 
mornings (0700-0830) and late night (2000-2400). 
Two reliable scribes query 4K2A — sounds like a new 
prefix for Dogger Bank! R. King relates that 5LZ 
was used by Liberian stations for two days, and 
Sweden is now issuing SK call signs. P. Johnson 
queries JX1RL and so do I. He says 7P8 is Lesotho 
and that Mexico (XE) is now 4A. I'm sure some 
countries' prefixes are taken from disused bus 
number plates. 

160/80/40 

J, Edwards (London, S.E.20), SX24, 137ft. end 
fed, discovered the following happily "at it" on 
160— G3SVK/P, GI5DX, GM30UU, GM30XX, 
GM3TSL/P, GW3TSH, OKIAUL OL1AJM, 
OL6AIU OL7AB, PA0AHO. On 80 metres— 
ET3USA VE1IE, W1FJZ/P/KP4, W2PNB, ZC4MO, 
3A2MJC, 4U1ITU. Forty metres— CM2DC, CN8CS, 
EA4JV, K3JH, PY2EGA, UA6KOE, VOIAK, 
WA1HXW, W2JA, 4X4QX. 

J. East (Worcester), R1475 (I remember dropping 
one of those on my foot!), 67ft. end fed, snuffled 
on forty armed only with his trusty b.f.o. Captures 
included— K3YWJ, K3ZNV, K4RSH/MM, 

K5YSO, PJ5MM, PY7AUT, UA5KD, W4KET, 
W8KMQ, WA6POD, YN2JF, YV1BI, ZP3AB, 
4A1CCW, 4U1ITU. 

S. Herod (Suffolk), R109A, 40ft. end fed, also 
braved 40 metres and hooked— CN8AW, CN8CS, 
EA8BQ, EA8EX, FP8CY, PY7ARP, UA9KDL, 
UV9CQ, VK3ZL, ZC4RB, ZP3AB. All these on 
s.s.b. 

P. Hampton (Worcester) says he's heard G3AOO 
in QSO with VK's most mornings at 0700. His log 
for 7Mc/s fair sends a tingle up "me" co-ax — 
CN8AW, K3ZNV, PZ1CF, VK2DO, VK2AHZ, 
VK3BM, VK3PB/M, VK3XM, VK7SM, YN2JF, 
ZL4BO, ZS1JA. I'll have to oil the alarm clock. 

20/15 

J>. Henbry (Sussex), HA500, 7ft. vertical rod at 
30ft. confesses to building the "Clubman" Mkll. 
Also contained in his statement was a 14Mc/s s.s.b. 
log from which the following are offered in evidence 
— FG7TI/FS7, FY7YL, F08BV, HC2RZ, 
HK0BKW, HS3DR, JW7YF, KH6EDY, KS6CL, 
KW6EJ, TA2BK, UA0NL, UI8LC, VQ9JW, VQ9V, 
VS9MB, XEIOE, XP1AA, YA1DAN, YN1GLF, 
ZD3D, 4A1WS, 5U7AN, 5W1AR, 7Z3AB, 
9K2BV, 9L2SL. 

H. Dearing (Goffs Oak), Super-Pro, 140ft. end fed, 



is s.s. s.s.b. (staunchly supporting single sideband) 
as the following log for 20 s.s.b. proves — CN8AW, 
CR6IS, ET3USA, HI3ELJ, HK5VS, JA6AUZ, 
KH6BZM, KJ6BZ, KL7EBK, OD5BV, PY1MK, 
PZ1PW, TG8IA, TG9EP, TF2WKP, VK1CN, 
VK20N, VK3WW, VK3AON, VK4DO, VK5WD, 
VK6FB, VK7ED, VK7RX, VK9GN, VP1BT, 
VP2GBG, VR6TC, XW8AX, YV5AG, ZL4BX, 
ZL4IG, 4A1AE, 4AILL, 4X4FQ, 4Z4HF, 5H3JL, 
7X0AH, and the best DX this month— G3JDG/M. 
(Aw shucks!). 

R. Spencer (Scarborough), SXI1I, PR30X, 20 
metre dipole, shuffled the 20 metre pack and dealt 
himself the following— A P2AD, CE0AE, DU1FH, 
FOSBS, FR7Zg (Reunion Is.), HS1AF, JA3KHV, 
JW2BH (Bear Is.), JX6AL, K8NHW/P/XV5. 
KG6AAY, KH6IJ, KL7MF, KR6KG, KR6MH, 
MP4BEU, TA2BK, VK3BM, VR6IV, VU2CT, 
VU2KO, XE2CO. XW8BQ, YA5RG, YV4ZJA, 
ZL4BX, 3A2CP, 4S7PB, 7Z3AB, 9Q5DG, 9M2NK, 
9N1MM— full house Sir! 

P. Batt (Lanes.), PCR3, 65ft. end fed only 6ft. 
high, heard these on 15 metres CT1AC, CT1ID, 
CX2CS CX4A, CX6BA, CX6EA, EA7MH, PJ30I, 
PY2CDY, WA4PBY, WA8GBE, W5KC, all on a.m. 
too. 

D. M. Clark (Bucks.), P.W. Progressive s.w. super - 
het, dipole for 21Mc/s, bagged these on 15 metres 
s.s.b.— DU1IK, EA8EX, EA9AQ, HL9KD, HS3DR, 
KG6EF, KH6BB, KX6FB, JA1AEA, JA2HTV, 
JA3KBP, JA6DHE, JA7UJ, JA8DSC, VK2FA, 
VK4TY, VK5GM, VK7GK, VK9LR, VS9MB, 
XW8BX, ZL1TU, ZL2LH, ZL3JO, 4A1CB, 
4S7PB, 5W1AS, 9M2PO, 9U5SK, 9X5MH. 

10 

Quite a bit of r.f. about in spite of the sun not 
being quite as spotty as it should. 

P. Starling (Essex), HR05T, 40ft. end fed, bagged 
these on 28Mc/s between 1400 and 1800— EL2X, 
ET3FMA, HK4AET, LU9DTA, OD5BA, PY1BLZ, 
PY6PQ, PY7VNY, SV0WL, UA6JWN, W4QKK 
W9EXE, ZC4MO, ZC4RB, ZE1BP, ZE6BNT 
5N2ABG, 5Z4LG, 9J2DT. 

P. Johnson (Northampton), RX60, 100ft. end fed, 
also went QRX on 28 for— CN8MI, CP3RCS, 
CR4BL, CR6CS, CR6KV, CV7CZ, CT2AA, 
CT3AS, EA8CV, ET3REL, HK4AB, HP9AAX, 
LU5DNT, PJ2CQ, PY2BG, SV1AE, UA9FBK, 
UI8DFP, W6UFG, W7WLL, W9IOV/MM, 
XE1CY, YV3NS, YV5ANE, ZS1BE, ZS2FA, 
ZS4CI, ZS6DT, 4X4JH, 5Z4BS, 9H1AV, 9J2AB. 

R. Dinning (Ayrshire), HA350 plus PR30X, 
252ft. end fed, queries I0ARI (no, it's not the Isle 
of Wight). He also heard— CR6KL, KG4CRC, 
LU1DAB, PZ1BF, UF6CR, VQ9JW, SV1AN, 
SV0WM, ZC4AK, ZD7KH, ZS5RS, 5Z4KT, 
9J2DT, 9K2BV, 9L2SL, 9X5 AA and Wl-0. 

CONTESTS 

Eyes down for a full house — 8th-9th June, UBA 
c.w. contest (80-10 metres); 8th-9th, National Field 
Day; 23rd, 70 cm. contest (portables); 24th, 2 metre 
s.s.b. contest; 6th-7th July, 160 metre contest. 



; " 



HEATH KIT Models for Family Entertainment 



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Moving coil record level indicator. Digital counter with thumbwheel zero 
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efficiency 8 x Sin. speakers. Operates on 230V a.c. supply. 
Versatile recording facilities^ So easy to build — so easy to use. 




Latest Portable Stereo Record Player, SRP-1 

Automatic playing of 16, 33, 
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Compact, economical stereo and mono record playing for the whole 
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KIT £28.6.0 incl. P.T. Ready-to-Use £35.4.0. P.P. 10/6 





Latest STEREO AMPLIFIER, TSA-12 

12x12 watts output 
Kit £30.10,0 less cabinet. P.P. 10/6 
Cabinet £2.5.0 extra 
Ready-to-Use £38.0.0. P.P. 10/6. 

FOR THIS SPECIFICATION 
17 transistors, 6 diode circuit. ± 1 dB, 16 to 50,000 c/s at 12 watts 
per channel into 8 ohms. Output suitable for 8 or 15 ohm loud- 
speakers. 3 stereo inputs for Gram, Radio and Aux. Modem low 
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8 Latest semi-conductors (6 transistors, 2 diodes). For 12 volt positive 
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Instant operation, no warm-up time. Tastefully styled to harmonise 
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8 x Sin. Loudspeaker £1.10.0 extra. 



JJIIllllll[lllllIlllltllll[IlllllllllilllllllIfltlI1llltltil]|1llllll1l1l]|[llll1lll[IIIIlllltlllI1IIIllFlllllirilll]lilliaillll3lllllllllltilllllilllltlt IIIIIHIIIIIIIHIIIIIIIIIIIIIIIIIIIINHIIIIIIIIIIIIIIII II 

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KIT £15.10.0 P.P. 6/- 

PORTABLE UXR-1 

This luxury 6-transistor, 1 diode receiver 
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Its robust case is now available in real 
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Powerful 10 transistor, 5 diode circuit. 

Tunes 580 to 1550 kc/s and 1-69 to 30 

Mc/s in five bands. Bandspread on all ^m 

bands. Fixed-aligned ceramic IF trans- _- 

filters for best selectivity. Pre-assembled || 

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17-18 St. Martins House, Bull Ring. 



Please address all enquiries to: 
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| □ Please send me FREE CATALOGUE 

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Deferred terms available over £10 (UK only). 

Prices quoted are Mail Order prices. Post and Packing extra. 



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Prices and specifications subject to change without prior notice. 



I 

183 



comt/MArm 




TYPEGDX 



TYPE GDX/25/C. Brand new fully transistorised 
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amateur bands, shipping bands, trawler bands, 
and broadcast band, A highly efficient double 
tuned superhet. comprising R/F aerial tuning 
section, AVC and built in tunable B.F.O. for 
C.W. or SSB reception. Operates from 9 volt 
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Hammer finished robust steel case of pleasing 
design. Size approx, 9 x 7 x 7in. British made. 
Equal in performance to sets costing three times 
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carriage and insurance 16/-. C.O.D, if required, 
ACCESSORIES : Headphones 19/6 extra, p.p. 3/6. 
Fitted S meter £2 extra. Battery eliminator 
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for TX/RX use. Will load almost anything. 
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Miniature Ilia, diameter moving coil speakers 
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each, p.p. 1/-. SHORT WAVE LISTENER'S 
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MONSTER PARCEL, Containing 50 electronic 
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STEREO HEADPHONES. British Made 30/-. 
Plus 5/- p.p. limited stocks. 

MORSE PRACTICE OSCILLATOR SET, 
Complete with "Hints on learning morse" 
manual. Fully transistorised. In compact case. 
19/11. P.P. 3/6. 

HEAVY DUTY DPDT SWITCHES. Centre off. 
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184 




TWO TRANSISTOR 



NUMBER TWO . . . in our beginner's series gives 
details for building a dual function two transistor 
receiver. It uses the minimum number of components 
— note that there are no resistors or coupling 
capacitors. 

LAST month, in part one of this short series, a 
receiver was described which used only one 
transistor plus two diodes in a reflex circuit. The 
second receiver, shown here, uses two transistors in 
a complimentary direct-coupled circuit. Although 
this sounds rather a mouthful it boils down to super- 
simple circuitry and practically no components. 
There are no resistors and no fixed capacitors and, 
unlike last month's circuit, no separate diodes for 
detection either. 

Dual-function 

One great advantage of this little receiver is that 
when the battery switch is off, the receiver will 
function as a crystal set. In areas of good signal 
strength, say for a local station, the switch can be 
left in the off position thus saving the battery. 







By T.SIMON 



Switching the battery into circuit boosts the signal 
very considerably. At the writer's home, a small 
transistor output transformer, connected in place of 
the headphones, allowed a small speaker to give 
very good results from the local station at Brook- 
mans Park on medium waves. 

Selectivity 

Although the set has only one tuned circuit, 
separation of stations was easily possible and no 
overlap was detected. This is probably due to the 
very high "Q" of the coil which aids the selectivity 
of the receiver. Normally, with 150ft. of wire for an 
aerial, both BBC1 and BBC4 tend to tune in together 
on a crystal receiver with a home wound coil. This 
is at the writer's home in St. Albans. In other loca- 
tions things might be better or worse, however, with 
such a large aerial, it speaks well for the selectivity 




Fig. 1: Circuit of the two transistor receiver. 



185 



of the receiver at being able to separate the stations 
so easily and successfully. 

Referring to the circuit shown in Fig. 1. The aerial 
is connected to the coupling winding on the coil LI. 
The signal is thus inductively coupled to the main 
tuned winding, and from here is fed to the base of 
the first transistor Trl via a low impedance tap on 
the coil. Transistor Trl is directly coupled to the 
second transistor, Tr2, in whose collector lead the 
headphones are connected. With the battery switched 
off, Trl functions as a diode feeding the signal to 
the base of Tr2. This second transistor might be 
considered as acting as a collector load for Trl. 

Polarity- 
Note that Trl is a p-n-p type whereas Tr2 is an 
n-p-n type. This is important for the circuit to 
function. The battery is connected in such a way as 
to supply power in the correct polarity to both 
transistors. The emitter of Tr2 goes to the positive 
side of the battery which is normal for a p-n-p tran- 
sistor. While the emitter of Trl connects, via the 
on/off switch, to the negative terminal of the battery. 
With the battery switched off, the diode action of 
the junctions of the transistors allows the circuit to 
function as a simple crystal receiver. With the battery 
switched on, the circuit will amplify the signal quite 
considerably. In this respect it is possible that too 



black 



BC108. 



OC171 



To yellow tag -^ 
on L1 




Fig. 2: Trl and Tt2 interchanged, but note battery polarity. 

much amplification will be present for the strength of 
signal entering the set. This will be characterised 
by distortion due to clipping of the signal wave- 
form. The solution is to use a smaller and/or perhaps 
a less efficient aerial. Or, if one signal is very loud 
while a more distant one much lower in strength, 
then the receiver could be used as a crystal set for 
the very strong signal, thus conserving the battery 
and avoiding the clipping referred to. 

Results with the prototype were excellent using a 
pair of high resistance headphones (2000ft), a good 
earth, and 1 50ft. of aerial wire. Very good results 
were also obtained from 40ft. of aerial wire with the 
same earth. 

Construction 

Construction is very simple but it is important to 
make sure of the connections to the transistors bear- 
ing in mind that one is p-n-p and the other n-p-n 
The transistor used for Trl might be considered a 
strange choice since these are usually thought of as 
useful for audio applications and not r.f. However 
the maker's specifications give the F T of the BC108 
as 150Mc/s typical, and thus it would appear well 
suited to medium wave circuitry. 

For those who would like to experiment it is 
possible to turn the circuit round and use the OCI71 

186 




Veroboard 

(drilled as 

top of 

chassis) 



Front 

Fig. 3: P/an view of the receiver showing positioning of com- 
ponents and the wiring. Note that there is a lower ring of tags 
on the coil. 

in the Trl position, and the BC108 in the audio 
stage. This circuitry is shown in Fig. 2, again the 
only points to note are the correct connection of 
the transistors with regard to polarity. 

Chassis 

The chassis is bent from a small scrap of alu- 
minimum and drilled as shown in Fig. 4. The front 
panel was made from a piece of thin Perspex which 
was to hand. Cut and drill as shown in Fig. 4. 
Note: Perspex cracks very easily so be very careful 
when drilling and filing. 

The piece of Veroboard is used mainly as some- 
thing to solder to. It is held to the chassis by the 
various bolts and also the coil. The tuning capacitor 
was glued to the Veroboard with Evostick applied 
along its bottom edge only. The coil mounts in the 
hole drilled and is held in position by its own 
threaded plastic nut supplied. The on/off switch 



.Front panel 



Cut-out ^ 6 x 1^ to clear 
battery contact fixing bolt 




Drill holes marked A /ij dta. 

B 4BA 

C 6BA 

Fig. 4: Drilling details for the chassis and front panel. Note — 

these details might alter with differing components. Check sizes 

etc., first before drilling. 

needs two 8BA nuts and bolts which may be pur- 
chased from most good ironmongers in a small 
plastic pack containing half a dozen. These bolts 
may need to be cut down if they are too long. 

The battery is a special Mallory type "which is 
rated at 5-6 volts. It is clipped into position with a 



small piece of springy brass, perhaps taken from an 
old cycle lamp battery? This is bent to shape and 
bolted to the chassis. Note that there is a hole cut 
out in the chassis so that this bolt does not short the 
battery to the aluminium. 

Wiring 

When all components are mounted wiring up can 
commence, but do not bolt the front panel on yet. 
It is all too easy to touch it with a hot soldering iron 
with gruesome results. Wiring should be carried out 
to conform with Fig. 1 and Fig. 3. Use a pair of 
pliers as a heat shunt when soldering in the tran- 
sistors. Leave clipping in the battery until the very 
last. Immediately prior to this, check again the 
connections to the transistors, remember that con- 
necting the battery in the wrong way will almost 
certainly destroy these devices. Check if you have 
used the alternative circuit shown in Fig. 2, if so 
have you orientated the battery correctly? 

Testing 

Connect the headphones to the collector of Tr2 
and earth, clip on aerial and earth leads but do not 
switch on the battery. Tune VCI from max to min 
and see if you can hear any stations. If you have 
ever built a crystal set and got it working in your 
area, then it is almost certain that this receiver will 
pick up the station(s). If you can receive more 
than one station, tune in to the weakest one and 



* components li 



Transistors: Coil: 

Tr1 BC108 Milliard L1 StabQoil type TMZ9 
Tr2 OC171 Milliard complete with trimmer 
TC2 (Electroniques) 
Capacitors: 

VCI 300pF midget solid dielectric 

Miscellaneous: 

Battery— 56V Mallory type PX23; midget on/off 
slide switch (G. W. Smith); high impedance head- 
phones (2000-4000O) ; small piece veroboard 1| x 
1|in. (nine strips); aluminium for chassis 2^ x lain.; 
piece thin Perspex 1 f x 2^in.; strip of brass § x 1 Jin.; 
three 8BA nuts and bolts; two 6BA nuts and bolts; 
wire* solder; aerial and earth wire. 



switch in the battery. The signal should be boosted 
quite appreciably. Having got the receiver working 
satisfactorily, you might like to try experimenting 
with the aerial. Try the bedsprings — mine work 
quite well with the battery switched in and no earth 
at all! 

There is no point in increasing the battery voltage 
since this will not increase the signal level to any 
significant degree. You might consider building a 
small case for the receiver for which almost any 
materia] would be suitable — plastic, wood etc. 

The coil shown in the photographs has its own 
"built-in" trimmer. This is not really required in this 
circuit and thus it should be ignored. It does not 
require any adjustment at all. 

NUMBER THREE . . . next month— a simple three 
transistor superhet receiver with a reflexed i.f. stage, 
and its own miniature "lin. speaker. 



we think 

these are 

SPECIAL 

- N 

A SIMPLE SIGNAL GENERATOR 

We think this one is special because 
it is very easy to build, plain uncompli- 
cated circuitry and you'll probably have 
most of the components in your junk 
box. Invaluable as an aid to servicing or 
any application where you need an 
r.f. signal. Wide coverage too — 720kc/s 
to 50Mc/s (200Mc/s on harmonics). 
We even tell you how to wind the coils. 

' 

. > 

1 WATT I.C. AMPLIFIER 

Almost unbelievable — 1 watt of 
audio from a tiny integrated circuit 
measuring f x\ x ^in. Two of these could 
be your answer to stereo. Complete 
"how to build" plus circuit for a 
suitable power supply. 



Details too for building a beginner's 
3- transistor superhet complete with 
its own midget Jin. speaker. 

There's lots of other articles too r so 
we say it is special — still not con- 
vinced? .Buy next month's bumper 
issue and find out for yourself. 



WIRELESS 

AUGUST ISSUE 

ON SALE FRIDAY, JULY 5 



187 



THE majority of purely "electronic" timers are 
dependent for their operation upon the length of 
time it takes a capacitor to charge up to, or dis- 
charge from, a given voltage. The charging and dis- 
charging processes are usually accomplished by means 
of a resistor, though a thermionic diode or valve is 
sometimes used. In the charging process, the valve or 
resistor is in series with the capacitor; in the discharging 
process, in parallel. 

Variation of the timing period is achieved by varying 
either R or C, sometimes both. Since C is usually one 
to several thousands of ^F, R is usually the variable 
element. The product of C x R is the time constant, and 
is in seconds when C=**F and R=Mf). This time con- 
stant can be maintained if either C or R is altered, by 
altering the other quantity by the same factor. 

In the practical circuit of Fig. 1 , C and R are represen- 
ted by CI, and R 1 to R12. The timing period is therefore 
variable in 12 steps, the shorter times being associated 
with the lower value resistors. Practical experience dic- 
tated the upper and lower limits, as well as the progres- 
sion, which is roughly logarithmic. In practice, the 
theoretical time constants are somewhat modified by the 
characteristics of two of the associated components. 
These are the timing capacitor itself and the first 
transistor Trl. 



the time constant to change in a random manner when 
the leakage resistance is of the same order of magnitude 
as the discharging device's resistance. 

The input resistance of a transistor is hfe xR E where 
hre is the gain and R E the emitter resistor. In parallel 
with this resistance is the leakage resistance of the diode 
formed by the transistor's base emitter contact. The 
former can be increased by increasing R E , and by using 
a transistor having a high value of hr e . The latter, by 
using a silicon transistor which has an inherently lower 
leakage, between base and emitter, than a germanium 
transistor. The timing period can also be affected by any 
variation in the voltage to which the capacitor is 
charged. Yet further variations can be caused by com- 
ponents altering in value. 



Circuitry 

In the circuit of Fig. 1 , constancy of the timing cycle is 
secured by using a good quality capacitor for CI and 
by choosing the constants so that the leakage resistance 
is appreciably greater than the discharging resistance; 
by stabilising the supply which is, of course, the voltage 
to which CI is charged; by using only good quality 
components used well within their ratings. 



( 




An ideal capacitor would, when charged up to any 
given voltage, and in the absence of an external discharg- 
ing device, hold that charge indefinitely. Very few capa- 
citors do. The reason is due to the inherent leakage 
resistance within the capacitor itself, which causes it to 
discharge over a period of time. This leakage resistance, 
which can be safely disregarded in many applications, 
can have serious consequences when capacitors are used 
in timing circuits. Not only does it limit theoretical cal- 
culations of time constant, particularly when long 
periods are involved, but, in my own experience, causes 



The operation of the circuit is quite simple. The mains 
voltage is reduced by T I to 9-0-9 V, is rectified by D3 D4 
and smoothed by C2. Stabilisation of the voltage at 9V 
is effected by D2, a 91V ±5% zener diode. R17 drops 
the surplus voltage, with Tr2 cut off, at the zener's 
working current load of approximately 20mA. In the 
prototype a value of 47Q proved to be just right. As Tr2 
draws a current of 16mA when conducting, the line 
voltage remains virtually unaltered at 9V, the zener and 
Trl accounting for the current difference. 

Capacitor CI is connected to the central or 




Fig. 7: Circuitry for the electronic darkroom stopwatch 



188 




.MAINS iSAFELjGHTS ENLARGER 
INPUT i '& i % OUTPUT 



MAINS 



ON 



ON 



STARTS 



Ol 




changeover section of the relay contacts designated 



RLA. 

1 

In the normally off position when Tr2 is non-conducting, 
this capacitor is connected to the supply line via the 
anti-surge resistor R13, and when the supply is on, is 
charged up to the supply voltage. 

When the relay is conducting, the changeover contact 
moves and connects CI to the base of Trl via R14, and 
via SI to one of the discharging resistors Rl to R12. 
Since Trl is an emitter follower, a proportion of the 
voltage to which CI has been charged, typically 95 %, 
appears across VR1. A further proportion of this volt- 
age, depending on the setting of VR1 , is therefore passed 
on to the base of Tr2 via R16, and causes it to conduct, 
pulling the relay on. The result is that C 1 is held connec- 
ted to the base of Trl until it is virtually discharged 
When this happens, the voltage across VR1, and hence 
the base of Tr2, is too low to cause it to pass sufficient 
current to hold the relay on. As soon as the relay drops 
out, CI is reconnected to the supply line, is recharged, 
and is ready for the next duty cycle. There is no delay 
and the next cycle can be initiated as soon as the user 
wishes. 

Initiation of the timing period is effected by SI. This 
is a miniature spring loaded "press to make" switch, in 



series with 



RLA 



contacts and R 1 5 . The 



RLA 



contacts 



2 2 

are normally on, when the relay is off. When the relay is 
pulled in, these contacts open, S2 causes the base of Tr2 

RLA 

to be connected to the 9V supply line via the — - — con- 



* components li 



Capacitors: 

CI 2500/xF 30V 

Resistors: 

R1 1 kn 5% 

R2 1-5kl)5% 

R3 2ka 5% 

R4 3ka 5% 

R5 5kO 5% 

R6 7-5kn 5% 

R7 10k£2 1% (see text) 

R8 1 5kQ 5% 

R9 20k£3 5% 

Semiconductors: 

Tr1 2N2926 green spot 
Tr2 ASY28 
D1 OA1 

Switches : 

51 1 pole 12 way 

52 press to make 

53 single pole on/off 

Transformers: 

9-0-9V 80mA Osmor 

Relay: 

500H coil 



C2 250uF15V 



R10 
R11 
R12 
R13 
R14 
R15 
R16 
R17 



D2 
D3 
D4 

S4 
S5 
S6 



30k a 5% 
40k« 5% 
60 k Q 5% 
220 a 1 0% 
4'7ttQ 10% 
1 OkQ 1 0% 
lOkO 10% 
470 10% 



OAZ207 

OA10 

0A10 



single pole two way 
single pole two way 
double pole on/off 



contacts 



[RLA 

1 
RLA 

2 
RLA 

3 



light duty changeover 



light duty normally closed 



heavy duty normally open 



Plugs and sockets: 

3 pin, Bulgin, miniature 



tacts and Rl 5. This causes the base voltage of Tr2 to rise, 

so causing an increase in collector current and the 

pulling in of the relay. Immediately this happens, CI is 

RLA 
brought into circuit by — - — and the timing period 

begins. 
So much is obvious. Less obvious is the need for the 

RLA 

— - — contacts. Different ways of initiating the timing 

period were tried and the method finally used was found 

RLA 

to be the most reliable pro vided — - — contacts were in- 

2 

eluded. Omitting these contacts led to some variation in 

the timing period, depending on the length of time SI 

RLA 
was held down. By including — — contacts, yet another 

source of possible inaccuracy was removed, because as 



soon as the relay closes, 



RLA 



contacts open, and con- 



tinuing pressure on SI cannot affect the timing period. 

Capacitors 

The Daly capacitor used for CI has, over a period of 
time, proved reliable. It is desirable to use a capacitor 
with a working voltage in excess of that actually re- 
quired, as leakage increases as the working voltage is 
approached. Also, the capacity marked on the capacitor 
is only nominal, the tolerance often being -i-100% and 
—50% of nominal. Obviously, this can have a marked 
effect on the timing periods obtained in individual cases. 



189 



To RLA 



The transistors chosen have 
excellent characteristics as well 
as being expensive. Tr2 could be 
replaced by an n-p-n germanium 
transistor of adequate rating. It 
is, however, advisable to retain 
Trl as specified, which is a green 
spot 2N2926 having a htm of 470. 

The relay could possibly prove 
difficult to obtain locally in some 
areas, though it should be ob- 
tainable from nationally adver- 
tised sources. Provided the re- 
quisite contacts are there, coil 
resistances between 500 and 
1,0000 should prove adequate. 
By adjusting R17 or even dis- 
posing of it altogether, and by 
changing D2 for a higher rated 
component, lower coil resis- 
tances could be used, without 
exceeding the maximum wattage 
rating of Tr2. This is because 
when Tr2 is non-conducting its 
collector is at supply potential. 
The products of Ic x Vs, where 
Ic is collector current and Vs 
supply voltage, is well below 
the maximum permitted dissipa- 
tion. Similarly, when Tr2 is 
conducting, it is virtually bot- 
tomed, and again IcxVc or 
collector to emitter voltage, is 
well within the maximum per- 
mitted dissipation. There is 
therefore room for experiment 
with varying coil resistances, 
provided Ic is always monitored 
and the maximum ratings are not 
exceeded. 

Some saving in expense can be 
effected by omitting the zener 
diode. In an area of stable mains 
voltages, the effect upon timing 
periods will be minimal. Varying 
mains voltages, as in my own 
area, could cause some variation 
in the timing periods. Although 
these variations can be masked 
by the tolerance of the printing 
papers, experienced "enlargers P* 

(or perhaps more correctly, enlarging operators) will 
know that optimum print quality can only be obtained 
when all variables are reduced to their precise, correct, 
proportions. Thus the slight additional expense of the 
zener diode is considered justified. 

Resistors 

Resistor R17 should be chosen, assuming the recom- 
mended relay is used, to allow approximately 20mA to 
flow through the zener with Tr2 non-conducting. This is 
sufficient to adequately stabilise the line voltage with 
Tr2 passing some 1 6mA when "on", whilst allowing a 
few mA spare in case the mains voltage should rise. The 
timing resistors must be hi-stabs of 5% or better 
accuracy. The progression chosen is logarithmic with 
alternative times being halved or doubled. If the 
enlarging lens has the more modern click stops where 
the light output is exactly $, J, |, etc., of wide open, these 

190 




OV supply (-ve) connected to 
chassis via metal spacer; 

Fig. 2 (above): Suggested layout and p.c. board pattern. 

Fig. 3 (below): Layout of the p.c board and other 
components. 




Fig. 4 (below): Wiring of the sockets and remaining switches. 




<t- 



Holes w.Kf 



*16 ** 



<4 dia. 
; To suit switch 
.6BA eieat PC fixing holes to suit PC board 



T— 



--0-- 



% 



© 



3 * 

■ ^A 



2% 



-te- 



rn 



i z 



"'&■ 



<£ 



2^; 



i 

— ( — 

i 

i 
I 

— |— 
1 



Bend down 






*M* 



m 

j 

# 

H 




Fig. 5: Drilling and layout details for the case f chassis. These are not critical and may need to be varied if odd components are used. 



times will prove most useful. Initial exposure, whether 
by meter or test strips, can be determined with the lens 
wide open. The lens is stopped down as required and 
the timer adjusted to suit. 

Diode DI across the relay must not be omitted. When 
the transistor "switches off", very high induced back 
e.m.f. voltages are present across the relay coil and 
transistor. This back e.m.f. is in the form of a pulse of 
opposite polarity to the supply voltage and could 
damage the transistor. The diode across the coil short- 
circuits this pulse and therefore protects the transistor. 

The timing circuit, with the exception of the relay and 
ancillary switches, is built on a piece of p.c. board 
measuring 5 x4Jx T Vin. The layout is shown in Figs. 
2 and 3. The use of heat shunts for soldering the semi- 
conductors and range resistors is recommended. 

Calibration 

For ease of testing and calibration, the timer should 
be assembled out of its case, coupled to the relay and 
S2 by means of flexible leads. After switching on the 
mains, the voltages should be checked, and should agree 
with those given. The zener diode and Tr2 emitter cur- 
rents can be checked, bearing in mind that as one 
increases, the other decreases, and vice versa. The 
currents given arc min. and max. The values allotted the 
timing resistors include one or two values that may 
prove hard to obtain in some areas. In this case, they 
may be made up of a series/ parallel combination. The 
5kfi resistor could thus be obtained from two lOkO's in 
parallel, and so on. 

The use of a stop watch is of the greatest assistance 
during calibration. Failing this, the seconds hand of a 
clock or wrist watch may be used. The procedure is 



quite simple. A suitable time, for example the ten second 
position of SI, is selected with the wiper of VR1 at the 
Tr 1 emitter and of its travel, S2 is depressed, whereupon 
the relay should pull in smartly. If it does not, but its 
armature is seen to move, R 1 5 can be reduced in value 
until it does pull in smartly. If it does not move, connect 
a voltmeter (0-1 OV) across VR1 and close the armature 
by hand. As soon as CI is brought into circuit, approx. 
8-5V should appear across VR1 , and via R16 to the base 
of Tr2. The voltage across VR1 will begin to fall, and it 
may be necessary to release the relay and depress it 
again. The collector voltage of Tr2, whilst Tr2 is cut off, 
will be virtually supply voltage. As soon as CI is 
brought into circuit, and assuming the earlier stages 
check out satisfactorily, the collector voltage should fall 
to about IV above earth potential. If the relay does not 
now move, the fault is almost certainly mechanical, or, 
perhaps, the coil resistance is incorrect. 



If the 



RLA 



contacts are present in the relay actually 



used, R15 can be reduced drastically or even dispensed 

RLA 
with. If the — - — contacts are absent, Rl 5 must be kept 

as high in value as practicable with reliable operation. 
It must not be removed from circuit under these circum- 
stances as it is quite possible to burn out Tr2 by holding 
S2 closed for an excessively long time, A "vacuum state" 
anology; connecting the grid of a value to h.t. ! 

Assuming all is well, the time obtained in the ten 
second position should be noted. It will almost certainly 
be in excess often seconds, in which case VR1 is reduced 
and another check is made. After several attempts it 
should be possible to obtain a time of ten seconds 
precisely. As this is the ''calibrating" range, and as lOkQ 



191 



is a preferred value anyway, a 1 % resistor is recommen- 
ded for this position. This is to ensure that the other 
ranges have a "standard time" to be checked against. 

The other ranges are similarly checked, except that 
VRI is not touched. Assuming a good capacitor for CI, 
and accurate range resistors, the times obtained should 
be in substantial agreement with the nominal times 
marked on the dial. Times shorter than those marked on 
the dial will require additional series resistors; longer 
times, additional parallel resistors. 

Constructors who feel that fixed, stepped times are 
unsuitable for their particular use, could replace SI, 
R1-R12 with a variable resistor having a value commen- 
surate with the longest time required. The disadvantage 
of a continuously variable timer is in accurately cali- 
brating very short times, plus the difficulty of reproduc- 
ing these short times accurately once changed to a longer 
time. 

The disadvantage of a fixed, stepped timer, is the time 
required to accurately select the timing resistors. The 
long and short term accuracies can be very high, whilst 
there is no resetting error. 

Once working satisfactorily, the timer can be mounted 

in the cabinet. The p.c. board in the prototype was 

mounted at three points, by means of 6BA bolts having 

|in, spacers between the p.c. board and the panel, the 

bolts also serving to hold the Perspex facing the panel. 

The legends are drawn with indian ink upon thin white 

card which is clamped between the Perspex and the 

front panel. 

RLA 
The ancillary switching is shown in Fig. 4. The — r— 

contacts control the current flow to the enlarger lamp, 

and are normally open. The focus switch S5 performs 

„ RLA 

two functions. In position 2 it is in parallel with —=-- 

contacts and allows the enlarger to be focused, or to be 
used for timing periods longer than that allowed by 
S1/R12. In this position it switches off the safelight 
which is normally not required during focusing, par- 
ticularly when large enlargements are being made, or 
when the negative used is very dense. If required, how- 
ever, the safelight can be switched on by S3. 

In. position 1, S5 brings one of two safelights used, 
one for reflected, one for direct lighting, into operation, 
the safelight used being selected by S4. S6 switches the 
mains supply to the timer and is the mains switch. The 
ancillary switching adds greatly to the flexibility of the 
timer which has proved, over a period of time, to be 
consistently reliable, ■ 



KEYLESS ORGAN 

— continued from page 173 

drill, apply to the hole giving a twist with the fingers. 
When finished each plate is like a small mirror, 
and an attractive feature when laying on the coloured 
felt in the completed instrument. Now place plates 
polished side up and in a row with long sides adjoin- 
ing. With a black wax pencil number from left to 
right from 1 to 37, above the screw holes. Below 
the holes write C, C sharp, D, D sharp, E, F, F sharp, 
G, G sharp, A, A sharp, B. (This should be num- 
bered 12), repeat this sequence twice more and mark 
No 37, C. The wax pencil will plainly mark the 
polished surface, will not scratch, and can be easily 
rubbed off later. 

Resistance Tuning Strip 

We require the fin. wide strip of hardboard for 
the resistance strip. Make a pencil line right down 
the centre, on the smooth side. With a pair of dividers 
set to rgin. starting fin. from one end, mark off 37— 
iMn. spaces along this line, prepare for drilling with 
a punch mark on the centre line at each division. 
Drill the holes, to take the 6BA screws, with a clear- 
ance drill, and avoid making the holes too large. 
With a medium file laid flat on the underside, rub 
along the strip to remove any extrusion left by the 
drilling. The strip is now trimmed off fin. from the 
last hole. 

Lay the strip down on a flat firm surface, smooth 
surface uppermost, with a piece of medium glass- 
paper placed around a small block of wood, rub 
from end to end along the top smooth side of the 
strip. Keep the block flat and avoid any rounding 
towards the edges. This is to remove the smooth 
surface and leave it slightly scored. A short worn 
down piece of HB pencil is now required. Remove 
the wood, half-way from an inch of the pencil leav- 
ing the lead exposed and half embedded in the 
wood. Rub the exposed lead flatwise on the rough- 
ened side of the strip, and rub well all over from 
end to end. The resistance strip should now be placed 
on one side, until the plate contact board is 
prepared. 

* Back issues containing details of the author's prototype organ that 

appeared in this magazine during 7965, are out of print and therefore 

we regret are no longer available from this magazine. 

TO BE CONTINUED 



PRACTICAL TELEVISION 

PULSE AND PATTERN GENERATOR 

A semiconductor 625-line pulse and video pattern 
generator built on perforated board and giving in 
addition to mains-locked sync pulses horizontal and 
vertical bar and checker-board patterns. 

COLOUR RECEIVER A.G.C. 

Current colour receivers all use the sync tip system, 
described in this article, in which the sync tips are 
the reference level for 3.g.c. action. In addition on 
405 lines many receivers use a ringing circuit also 
described, to give gated a.g.c. action. 

X-RAY RADIATION 

The first part of a short series on electromagnetic 
radiation with special reference to television problems. 

JULY ISSUE ON SALE JUNE 21 



July issue on sale June 14 


* DRILL SPEED CONTROLLER 

-k MULTI- CHANNEL RADIO- 
CONTROLLED BOAT 

ic WAA-WAA: EFFECTS UNIT FOR 

ELECTRONIC GUITARS 


PRACTICAL ELECTRONICS 



192 




BANNING the critics from 
the premiere of his epic, 
The Charge of the Light 
Brigade, film director Tony 
Richardson called them '. . . A 
group of acidulated intellectual 
eunuchs, hugging their prejudices 
like feather boas." He commen- 
ted that one of the many indi- 
gencies the critics permitted 
themselves was to talk "honestly" 
about their own prejudices, 
imagining that this would make 
them even more lovable. 




This critic in a feather boa. 

Well now, this critic makes no 
claim to cuddly lovability, and 
would probably look even less 
prepossessing in a feather boa, 
but he must admit to a few 
prejudices. 

So he must join with the 
Editor in deprecating the unsatis- 
factory episode of Ted Short's 
throw away line in the Commons 
about the Beginners' Licence. 

Henry has no particular claim 
to a vested interest in B licences 
or any form of rad ionic L-plate. 

Nevertheless, this matter is im- 
portant to anyone who dabbles in 
wireless, whether or not he has 
ever bashed a key in anger. 

Should we throw open the air- 
ways to all, or restrict the bands 
to those with sufficient sense of 



responsibility to take what is, 
after all, quite a simple test? That 
seems to be the crux of the argu- 
ment. 

This projected Beginners' 
Licence could be like the Ameri- 
can "Novice Licence". 

We shudder to think what that 
could mean. As recently as 
April 1st, we saw the ban on sales 
of imported Citizen's Band Equip- 
ment come into force. This 
27Mc/s stuff is still widely adver- 
tised, and, we suspect, available 
under the counter. All manner of 
unlikely applicants will now be 
lined up to chip loopholes in any 
fence the PMG may choose to 
erect to safeguard the Beginners* 
Licence. But as to what our loyal 
band of hams will say to a pos- 
sible restriction of their air-space 
— that would hardly be covered 
by the Q-code. 

There are plenty of existing 
restrictions. The A licence per- 
mits telegraphy and telephony on 
all h.f., v.h.f. and microwave 
bands. The City and Guilds of 
London Institute set a Radio 
Amateurs' Exam, that should not 
daunt the determined. And surely, 
12 words a minute with the morse 
key is not asking too much, even 
of an under-fourteen contender, 
which, I understand, the new 
licence may admit? 

We must wait and see whether 
the proposed Beginners' Licence 
will be used as an incentive to 
those wishing to progress toward 
a full ticket — or some bending of 
the rules to placate a vested 
interest. 

One of my short-wave enthu- 
siast colleagues grunted: "For 
Licence read License." And if 
we extend our vision a bit he is 
not far wrong. Think of the over- 
crowded m.f. and l.f. bands which 
makes all but the most local of 
programmes an aural obstacle 
course. 

The Copenhagen Plan author- 
ised 600 stations on Medium and 
18 stations on Low Frequen- 



Ho. 46 

Air Shares 
For All 



cies. But not all countries were 
parties to the Plan, and there is 
no international air-space police 
force. The price of freedom has 
been a 226 per cent increase of 
m.f. stations (power going up 230 
per cent), 1360 stations on m.f. 
against the original 600 and 28 
on l.f. against the original 18 — 
that's a heck of an argument 
against overcrowding. No wonder 
the pirates were banned. Pity 
those eight blighters that do noth- 
ing but jam could not be boarded 
also! 

What is the answer? Despite 
the BBC's plugging of v.h.f., there 
is a real need for both m.f. and 



^V 




Available under the counter. 

l.f. communications. The partial 
solution of day and night band- 
sharing that the USA has toyed 
with does not go far enough. 
S.S.B. seems to be the best solu- 
tion — but that has its snags. 

Recently, Georges Hansen, 
technical director of the EBU 
and H. Eden of the Institut fuer 
Rundfunktechnik, have suggested 
non-compatible single sideband 
transmissions as being the only 
way of sharing the bands without 
adjacent channel interference. 
The implications, much as we 
heard ad nauseam when the 
colour TV controversy was 
raging are that we should need 
new sets, and because of the need 
for synchronous detection, the 
cost of these would be higher. 



193 



PART 4 



H. W. HELLYER 



Cabinet appearance and care is important, 
and attempts at repair when damaged can 
often end in disaster unless you have the 
know-how . . . 




YOU may perform miracles of electronic diag- 
nosis; you may dig out of the spares box all 
the transistors and components you need; you 
■may wield your soldering iron with consumate skill 
. . . but just wait until you hand the repaired 
receiver back to the lady of the house. If it has a 
tatty cabinet, all your good work was in vain. 

Appearance matters. Repairs often entail small 
rejuvenating touches to woodwork and plastic, and 
unless you know what you are doing, the end result 
can be disaster. 

Woodwork — even for transistor radios, for the 
modern trend to wood finishes, even if it fades out 
temporarily, is sure to come around again when our 
designers feel the seven-year itch. Different woods 
need different treatment. Veneers require great care, 
and some of the artificial wood laminates present yet 
more problems of their own. 

Very often a damaged cabinet will not respond to 
any patching or camouflaging: it may be necessary 
to re-colour or re-cover it. The success of a recent 
gay-colour range of television receivers prompts one 
to suggest that this sort of treatment may occasionally 
be a good thing. First requirement is to remove all 
the appendages, knobs, escutcheons, etc., that can be 
removed, and carefully mask all those that cannot. 
When masking, always use a simple, form of tape or 
paper with an innocuous adhesive. Lettering on 
panels or glass dials is so easily damaged by being 
"lifted" when the adhesive surface is stripped — and 
this point must be considered before you begin. 
Remember that ordinary adhesive tape of the 
transparent variety can become very tacky with 
heat, and will tend to leave an edge mark when 
removed. Although the material is more expensive, 
the cellulose tape as supplied to radio dealers by 
Messrs. Radiospares is very suitable for odd jobs of 
this nature. It can be stretched slightly, thus giving 
a more intimate bond, and the adhesive is not des- 
tructive to cabinets and laminate finishes. Readers 
will undoubtedly be able to suggest alternatives. 

If masking a straight edge, do not fiddle with the 
tape to get an accurate line, but overlap slightly, 
press and smooth the tape, then trim the surplus 
tape with a razor blade, or some form of patent 
cutter, angling this inwards so that the cutting 
motion also tends to take the edge of the tape under 
the panels, etc., presenting a cellulose surface to the 
stain or paint rather than the necessarily rougher 
edge of the tape. A neater completed job will 
result when the masking is removed. 

Covering a curved surface can be rather more 
tricky. It is best to use a similar approach, i.e., to 



overlay in a series of straight pieces, then trim as 
before. A useful dodge when doing small touch-up 
jobs with cellulose paint or any high -gloss touch ing- 
up medium, is to mask by simply painting over the 
protected surface with grease or even water-colour 
poster paint. This need only be done at the edge 
where the two surfaces meet, to prevent the hard 
gloss paint or stain running beyond its required 
limit. Then, after the main body of the work has 
been finished, the grease can be cleaned off with a 
lint-free rag, or, except in the case of cellulose sur- 
faces, a cloth damped slightly with methylated spirit. 
The other problem is lettering. All too often 
this is stencilled on the main panel, and to colour 
round it is, except for a master forger, a much too 
formidable task. Why not consider renewing the 
legends completely? There are sets of symbols, 
words, individual letters and signs in a multitude of 
styles now available. Most of them go on the 
finished smooth surface as easily as the transfers we 
got smacked for sticking on our wrists when we 



Cut in at an angle 




Fig. 20: Masking curved sur- 
faces presents problems. 
The tape can be applied 
quite roughly, then trimmed 
to the shape of the raised 
portion cf the cabinet, using 
an angled cut with a sharp 
blade to fold the masking 
tape inwards, as shown. 



were young. Some of those offered as a free gift 
in a recent issue of this journal can be used to 
improve upon a manufacturer's design with telling 
effect. At least, one has an original piece of appara- 
tus to show for one's efforts. 

Touching-up may not be good enough for you. 
Nothing is as good as a completed job in true wood, 
you may argue. This approach is especially valid 
when loudspeaker cabinets are being constructed. 
Timber is still one of our best materials, despite the 
proliferation of plastic substances. And there is 
something opulent about the look and feel of true 
wood surfaces that pleases the constructor. There 
are one or two points he must remember, however, 
if he is not an experienced handyman. This article 
cannot go too deeply into woodworking — evep if its 
author was qualified to deal adequately with the 
subject! — so do-it-yourselfers, and regular subscri- 
bers to Practical Householder must forgive a few 
relevant points thrown off at random. 

Before we attempt to do any colouring at all, 
there is the very necessary preparation to consider. 



194 



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SEVEN WAVEBAND PORTABLE AND CAR RADIO WITH A SUPER 
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9 7 FULLY TUNABLE WAVEBANDS— MW1, 
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MW2, LW, SW1, SW2, 



Estra tuning of T^nxerubnurg, etc. 



BuiJt in ferrlta rod aerial for Medium and 
Lnng "Waves. 



5 Section '22 inch chromts plated telescopic 
aerial for Short Waves — can be angled and 
rotated fur peak S,W, listening, 

Socket [nr Car Aerial. 

Powerful pusii pull output. 

7 translators and two diode* including 
Fhilco Miero-AJloy E.F. Transistors. 



Air apteed gaaffad tuning Londcnser, 



# Separate on.'oll switch, vnhiine control, 
w;tve change switches and tuning control. 



Attractive case with hand and ahoulder 
straps. Size 9lu. x 7in, x 4iti, appro*. 



• First grade component? 



Ea«y to follow instructions and diagrams 
make the Ko&mcr 7 a pleasure to build with 
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Total building costs 

£5.19.6 



p. &p. 

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Total building costs 



426 



p. & p. 

4/6 



MEDIUM WAVE. LONG WAVE 
AND TRAWLER BAND PORTABLE 

Attractive case with red speaker grille. Size 6| i 
41 x 1J in, Fully tunable, 7 stages — B transistors 
and 2 diodes, ferrite rod aerial, tuning condenser, 
volume control, fine tone super dynamic 3f in. 
speaker, all first grade components. Easy buiid 
plans and parte price list 1/6, (FBEE with parts). 




Parts price list and easy 
build plans 3/- with ( Free parts) 




Total building costs 



P. & P. 
4/6 



396 



MEDIUM WAVE, LONG WAVE 
AND TRAWLER BAND PORTABLE 

Attractive black and gold case. Size 51 z li x 
3}in, Fully tenable over both Medium and Loag 
Waves -with extended H.W. baud for easier 
tuning of Luxembourg, etc. All first grade com- 
ponents— 7 stages— 5 translators and 2 diodes, 
supersensitive ierrite rod aerial, fine tone 2jin. 
moving coil speaker etc. Easy build plans and 
part* price list. 1/0 (FREE with parts}. 




NEW MELODY MAKER SIX 



3 WAVEBAND PORTABLE 



8 stages — 6 transistors and 2 diodes 



Covers Medium and Long "Waves and EXTRA BAND FOR EASIER TUNING OF LUXEMBOURG, eto. Top quality Sin. Loud- 
speaker for quality output. Two HF stages for extra boost, lllgb "<J". Ferrite Rod Aerial. Push-pull output. Handsome 
pocket size case with gilt fittings. Size 6i x 3J x lira. 



This amazing receiver 

may be built for only 



69/6 



P. & P. 4/6 



Parts Price List and easy build plans 2j— 
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Total building costs 



79'6 



p. & p. 

4/6 



Attractive case with *Mlt jit rings, size 71 x 5$ x 
l^in. World wide reception. Tunable on Medium 
and Long waves, two short waves. Trawler Band 
Plus an extra M.W. baud for easier tuning ol Lux- 
embourg, etc. Sensitive ferrite rod aerial and 
telescopic aerial lor Bhnrl waves. All top grade 
components, 8 stages— -CS transistors and 2 diodes 
mchidlng l'hilco Mtaro-ADo? R.F. Transistors etc. 
(Carrying strap 1/6 extra.) Basv Lulkl plans and 
parts price Hat 2/- (FEEE with parts). 




Total building costs 

69'6 Ve p 



Attractive case size 7 r i S| i l}ln. with gilt 
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Covers Medium and Long Waves and Trawler 
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build plans and parts. Price list 2/* (FUEE with 
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RADIO EXCHANGE CO. 



Callers side entrance Stylo Shoe Shop • Open 9-5 p.m. 
Saturday 9- 7 2.30 p.m. 



61 HIGH STREET, BEDFORD 
Telephone: Bedford 52367 



195 



This may sometimes seem tedious, but the finished 
result will greatly depend on the trouble we took 
at this stage. All holes must be stopped or filled and 
the filler rubbed down to level exactly with the main 
surface. Small grooves, scratches or protrusions 
become very noticeable when the job is polished, 
the more so if a high gloss finish is used. Even when 
merely patching-up damage, the primary rubbing- 
down is worthy of a great deal of care. 

For basic wood and some plywoods and laminates, 
a sanding block is useful. This is simply a rubbing 
block with flat faces, on to which sandpaper can be 
fastened. Starting with coarse grade and gradually 
working towards the lower number, i.e. finer grades, 
the wood is rubbed down along the grain to give a 
surface smooth to the touch and even to the view, 
when inspected along its edge plane under a strong 
light. For a final rubbing down, a cork block in place 
of the more solid wood will allow the sandpaper 
sufficient "give" to achieve a satiny finish. 

Small holes and cracks can be filled with a putty 
filler, plastic wood or one of the many water -mixes 
available. When using putty filling, remember that 
the oil in it will tend to seep into the wood. These, 
and some of the water-mix preparations, shrink as 
they dry. Therefore it is necessary to overfill, allow- 
ing the stopping to stand "proud" of the surface and 
dry, then sand away the surplus, Experience tells 
us just how much to allow extra, but for odd jobs, we 
must err on the liberal side. 

Stained hardwoods can look very effective. Oil, 
wax or french polishing methods can be used, 
though the last mentioned needs a lot of patience 
and careful control of conditions. Dust is absolute 
anathema to cabinet polishing, so do not get on 
with other constructional work in the same room 
while waiting for the polish to dry. Oil staining 
can be fairly quick and easy, with the oil laid on 
thickly, then the surplus wiped off, and the process 
repeated until the required shade is obtained. End 
grains must be treated with more care, being more 
porous, and tending to soak up the oil, leaving a 
darker finish. 



WATER STAINING 

Water stains are not so easy. They need more 
applications, and one approaches the darkening 
process gently, even though the stain itself is fairly 
quick-drying and simple to use. An emergency water- 
stain that can be used to protect a natural wood 
and simply darken its colour, is obtained from dis- 
solving crystals of potassium permanganate in water. 

Staining is not the end of the job, and one must 
never be tempted to go too far along this line or the 
surface will be darkened beyond what one needs. 
After staining, the grain must be filled to get a 
smooth surface, this filling rubbed down, and 
final polishing can then take place. There are 
numerous patent fillers on the market, and these 
are generally applied with a pad of cloth across the 
grain of the wood, beginning with a small area and 
gradually extending the action. A drop of linseed oil 
can then be wiped over the surface when the filler is 
quite hard — usually an overnight process. 

Deeper scratches may be filled as before, with 
polymer and plaster mixes, but it is always wise to 
incise the cut a little with a sharp knife or chisel to 



allow the filler a "key", and again remember to 
allow protrusion, then rub down. The shellac is then 
employed as a finish on top of the basic filler, and 
this will give a hard match for the original surface. 
Wide, shallow depressions can be filled with shellac 
and spirit mixture, with greater care being needed to 
obtain a level surface when rubbing down. 

Plastic cabinets need quite different treatment. 
Minor scratches can be removed on most plastics by 
patiently rubbing them down with metal polish. For 
deeper scratches, a rubbing compound should be 
used to smooth off the surface to its new, lower 
level, before finishing with the milder abrasive. But 
it must be remembered that the colouring of a plastic 
material is part of the construction, not added to the 
surface. Although this may make the job easier, in 
that we have no problems of matching, it will 
always mean that the polished part will be lower 
than the original. Thus it may be required to extend 
the area of polishing to camouflage this depression. 

Cracks and definite breaks offer more of a chal- 
lenge. It is sometimes possible to fill these with 
chippings from a less obvious part of the cabinet 
than that to be treated, i.e., foot ridges and so on. 
The chippings can be softened with a slight applica- 
tion of trichlorethylene or a similar solvent, taking 
great care not to splash this around, and the resultant 
paste is moulded into the crack after keying ridges 
have been cut. The solvent evaporates and eventually 
the plastic hardens, leaving a rough surface that can 
be rubbed down. 

It is even possible to repair clean splits by this 
method, moistening the edges of each side of the 
split with the solvent, pressing them together and 
clamping them until the plastic hardens — overnight 
is sufficient — -and then rubbing down and polishing 
as before. If you want to make a clean joint and 
avoid the polishing, use a fine pointed paint brush, 
apply the solvent along the edge of the crack with a 
bias toward the unseen surface of the cabinet, and 
let it dry a little, as when using a contact adhesive, 
before pressing the two parts together. This last 
operation needs a steady hand. The solvent tends 
to spread, and one shaky attempt can ruin a smooth 
surface. 

The join can be reinforced on the inside with a 
rougher seam, made by application of solvent and 
a "kneading" action, taking care that any protru- 
sions thus formed will not foul the innards of the 
receiver when it is reassembled. And always remem- 
ber that the solvent softens the material, so that 
excessive pressure or clumsy handling will irrevo- 
cably deform the plastic shell. These repairs need 
great patience — but can be immensely rewarding, 
and an aid to economy. Occasionally a hot soldering 
iron may be used on inner surfaces to "weld" a seam 
in plastic. 




Fig. 21: One method of plastic cabinet joint not always obvious. 

To release the two portions, gentle pressure is needed along the 

seam at the side shown arrowed. 



196 



PP3 Eliminator, Flay your pocket 
radio from the mains I nave £*. Com- 
pie te co uipone at kit comprises 4 
rectifiers — mains dropper resistance*, 
smoothing condenser and instruc- 
tions, only 6/6 plus 1/- post. 



FLOOD LAMP CONTROL 



Our dim and full switch is ideal 
for controlling; photo flood lamps 
it (fives two lamps hi series,, two 
lamps full brilliance and Lamps 
off. Similar control of other appli- 
ances can be arranged where used 
In pair or where circuit can be split 
exactly In half. Technically the 
switch \s known an a double-pole 
change over with off* Our price 4/8, 



I 



Timer Switch & Thermostatic Switch 

For control of oil fired boilers ami process ovens 
in (act aiij^ equipment where parts of it have to 
operate for short starting periods — but which will 
be switched off Immediately should a high enough 
temperature be reached. 

The clockwork mechanism with Jewelled escape- 
ment may be set for up to 4 cuius, and operates 
15 amp. changeover contacts. The thermostat 
cab bo set 7u o -300 o F and operates more switches 
directly the preset tnmperatun-. In reached. Made 
by Smith's Electrics brand new anil perfect 29/6 
each plus 2/9 post and ins, 

THERMOSTATS 

Type "A" 15 amp. for controlling room heaters, 
greenhouses, airing cupboard. Has spindle lor 
pointer knobs. Quickly adjustable from 30-80^, 
8/6 plus 1,'- post. Suitable box lor wall mounting 
6/-. P. & P. 1/-, 

Type "B" 13 amp. This is a 171n. Ion? rod type 
made by the famous Sunvic Ob. Spindle adjusts 
this from 50 a -5oO°F. Internal screw 
alters the setting so this could be 
adjustable over 30° to 1000°P, Suitable 
lor controlling 
furnace, oyen 
kiln immersion 
or to make flame-start or Ore 
a, 8/fl plus 2/6 post and insurance. 
Type "D'\ We call this the fee-slut as it cuts In 
and out at around freezing point, 2/3 amps, lias 
many uses one of which would lie to keep the toft 
pipes from freezing, If a length of our blanket wire 
(16 yds. 10/-) is wound round the pipes, 7/8, 
P. A P. 1/-, 

Typ» "E", This [s standard refrigerator thermo- 
stat. Spindle adjustments cover normal refrigera- 
tor temperature. 7/6. plus 1/- post. 
Type "F", Glass encased for controlling the temp, 
of liquid — particularly those in glass tanks, vats 
or sinks— thermostat Is held (hall submerged) by 
rubber sucker or wire clip — ideal for fiah tanks — 
developers and chemical baths of all types. 
Adjustable over range SO" to 1B0°F. Price 18/-, 
plus 2f- post and insurance. 




TAPE BARGAINS 

American made P.V.C. base 2S0ft. tape Ui 
message boxes (space provided for name and 
address of recipient) 3/9 each. 4 for 14/6 post 
paid. Other P.V.C, tape bargain 5in.-1800ft. 
35/B, 5in.-S50ft. 10/6, agin.-SIJOit. B/-, 5|in.- 
lUOOft. 11/6, ;i;i[i.-H00it. 18/6, Slin.-2400ft. 
32/8, 7in.-1200ft. 11/6, Tin,- 1800ft. 8/6, 7in.- 
24110ft. 35/-, 7in.-3flO0it. 42/6, 
A.E.I. FRACTIONAL H.P. MOTOB, 200)250 v. 
50 /SO c.p.s, enclosed, continuous rating 1/40 
h.p,, ex equip t. Perfect order 18/6 plus 4/6. 
A.C. FAN, powerful mains motor with rliin. 
blade, idea) blow or extract. 17/6 plus 3/6. 
1.&T, NICKEL CADMIUM CELLS, dia. Jin. by 
ilh, thick (approx.) 3/6 each, charger for two 
cells. 12/8, 

OH THERMOSTAT, Teddington type, T.B.B. 
with capillary tube and sensor adjustable by 
knob (not supplied), controls J h.p, motor or up 
to 15 am p, re sistive load, 8/8. 
5 PUSH SWITCH, one push operates mains mil 
off switch, the other four operate various on/off 
and change/over switches, 2/6. 



SNIPERSCOPE 



iwr&A-«&- 



S ENSITIVE LAW 

FLUOOESCENT 
SCDCEM 

A I VIEWWC WIHWvvJ J; 

Ms ?" ■ U J/ 



Famous war-trac 
"cat's eye" usud 
for seeing in the 
dark. This is an 
Infra-red image cou- 
verter cell with a 
si 1 ver caesium screen 
which Lights up (like 
a cathode ray tube) 
when the electrons 
released by the 
Infra-red strike it. A golden opportunity for some 
interesting experiments. 7/6 each, post 2/6. Data 
will be supplied with cells. If requested . 

FIELD TELEPHONE UNIT. Each unit contains 
magneto type ringer and bell — as well a? trans- 
former — relay and switches. A pair of these with 
suitable hand- telephone (not supplied) will give 
two-way communication over distances of up to 
5 miles. Unused but In stored condition. 18/6 plus 
10/6 carriage. 

Multi Purpose Neon Test Unit 

Robust, useful and Instructive— test* insulation — 
capacity — eontl nulty — resistor — volume controls 
— also acts as signal injector and L.T. fault lindor 
—kit comprises neon indicator — 4-way wafer 
•witch — ebonite tubes — resistors-condensers — ter- 
minals, etc. with diagram only 9/6, pins 2/- post 
and insurance. 




HI FI BARGAIN 

FULL FI 12 INCH LOUDSPEAKER. This is undoubtedly one 
of the finest loudspeakers that we have ever offered, produced 
by one of the country's most famous makers. It has a die-cast 
metal frame and is strongly recommended for Hi-Fi toad and 
Rhythm Ouitar and public address. 

FInx Density 11,000 gauss— Total Flux 44,000 Maiwells — 
Power Handling 15 watts R.M.S. — Cone Moulded fibre — Freq. 
response 30-10,000 c.p.s. — input Impedance 15 ohms — Main 
resonance (10 c.p.s. — Chassis Diam,12ln. — 12|in.ovcrTtii,iinti:-g 
lugs — Baffle hole llln. Dlam.— Mounting holes 4, holes— Jin. 
diam. on pitch circle UJIti. dlam. — Overall height aiin. A £6 
speaker offered for only £3.9.6 plus 7/6 p A p. Don't miss this offer. 



GARRARD 
Mode! 3000 

This is one of the latest products 
>f the "World's most experienced 
maker of fine record reproducers. Its 
superior features include — automatic 
playing of up to 8 mixed size records — - 
stopping and starting without rejecting 
— manual playing — pick- up pivots to give 
low stylus pressure — large diameter turntable for max, stability adjustments 
include pick-up height — pick-up dropping position and stylus pressure. Size is 
13} X 1 1 iln., clearance 411n. above. 2iJn. below — Fitted with the very superior 
ceramic stereo cartridge type 9TAHC with diamond stylus which is listed at 
jjver£4. Price complete 410.9.6, earr. and ins. 7/6. 




THtS MONTH'S SNIP 



Electric Clock with 20 amp. Switch 

Made by Smith's these units are as lilted 

to many top quality cookers to control the 

oven. The clock is mains driven and 

frequency controlled so it is extremely 

accurate. The two small dials enable 

switch on and off times to be accurately 

set — also on the left Is another timer or 

alarm — this may be set in minutes up to 4 

hours. At the end of the period a bell will 

sound. Offered at only a fraction of the 

regular price — new and unused only 39/6 less than the value of the clock 

alone — post and ins, 2/9, 




^—^^~ BARGAIN OF THE YEAR 
MICRO-SONIC 

7 transistor Key chain Radio in 
very pretty case, size 2] x2}x liin, 
— complete with soft leather zipped 
bag. Specification:— Circuit: 7 
transistor superheterodyne. Fre- 
quency range: 530 to 1600 Kc/s. 
Sensitivity: 5 mv/m. Intermediate 
frequency: 465 Kes, or 435 Kos. 
Power output: 40m W. Antenna: 
ferrite rod. Loudspeaker: Perma- 
nent magnet type. 
In transit from the East these sets 
suffered slight corrosion as the bat- 
teries were left in them but when 
this corrosion is cleared sway they 
should work perfectly— offered without guarantee except that they are 
new IB/8 plus 2/8 post and ins., less batteries. 





BATTERY OPERATED TAPE 
DECK 

With Capstan control. This unit is extremely 
weli wade and measures approx. 81B1 2in. 
deep. Has three piano key type controls for 
Record, Playback and Re win-.] . Motor la a 
special heavy duty type intended for opera- 
tion off 4/5 volts. Supplied complete with 2 
spools ready to inytall. Record. Rtsplay head 
is the sensitive M4 type intended for use with 
transistor, amplifier. Price £4,15.0. Peat and insurance 4/U. 

DRILL CONTROLLER 

Electronically changes -ipecd froni approximately 10 revs 

to maximum. Full powy rat a 11 speeds by finger-tip control 

Kit Includes all parts, case, everything and full instruc- 
tions. 19/6, plus 2/8 post 
and insurance. Or avail- 
able made up 32/6, plus 
2/6 F. A P. 

CENTRIFUGAL FAN 

CENTHIFU&AL BLOWER or extractor by 
Torrington, very low noise but large capacity air 
fiow, designed for central heating and air con- 
ditioning, ideal also for fume extraction over 
cooker, duct type outlet, 200-250v. 60 C.P.3. 
motor, £3.18.6 post anil Insurance 7/6. 

RADIO STETHOSCOPE 

Easiest way to fault find— traces signal from aerial to 
speaker — when signal stops you've found the fault. Use 
it on Radio, TV, amptiiler, anything — complete kit Com- 
prises lin ;prriii.l :n,n-i ■!.![■- and all parts Including probe 
tube and crystal earpiece 29/6 — twin stetoset instead of 
earpiece 7/8 extra — post and ins,, 2/0. 







CASSETTE LOADED DICTATING 
MACHINE 

Battery operated and with all accessories. "Really 
fantastic offer a British made £31 outfit for only 
£6.19.6. brilliantly designed for speed and efn- 
ciency- — cassette takes normal spools, drops in and 
out for easy loading — all normal functions — ac- 
cessories include: stethoscopic earpiece — crystal 
microphone has on/off switch — telephone pick-up 
—tape reference pad— DON'T M1BB THIS UN- 
EHFSATABLE O IT E R — SE \ D TO TJ AY £6. 1B.6 
p I us 7 /ft post and 1 n iu ranee . Foo ts wi teh 18/6 extra, 
Sparc Cassettes at 7/6 each, three for £1. 

MAINS TRANSISTOR POWER PACK 

Designed to operate transistor neta and amplifiers 
Adjustable output (Jr., 9^., 19 volts for up to 
500mA (class B working)- Takes the place of any 
of the following batteries: PPl p FP3, PP4, PFG, 
PPT. PP9, and others. Kit comprises: mains 
transformer rectifier, smoothing and load resistor, 
condenser? and Instructions. Real snip at only 
16/fl, plus 3/fi postage. 

CAPSTAN DRIVEN TAPE 
RECORDER. Only £5/19/6. 

(Batteries extra) 
Portable with built-in 
microphone ami Jmld- 
speakcrusing a 5 tran- 
sistor amplifier with 
~\ P. output. Opera* 
t.on by chargeable 
batteries. Tape 
capacity 25 

mills. Tape 
position In- 
dicator* Ttecord- 
log level auto- 
matically preset. 
Inter-lock pre vents tmintetitlonal erasures. Tape 
speed controlled by flywheel driven capstan. Neat 
case wifeh carrying handle, size appro*. fi£ x 7 \ r 
Sin. Postage and insurance 7/6. 

MAIMS MOTOR 

Precision made — as used 
in record decks and tape 
recorders — Ideal also lor 
extractor fans, blower, 
heater,, etc. New and 

Perfect. Snip at B/0. 

Postage 3/- for first 
one then 1/- for each 
one ordered. 12 and 
over post free. 





FLUORESCENT CONTROL KITS 

Bach kit comprises seven items — Choke, 2 tube 
ends, starter, starter holder and 2 tnbe clips, 
with wiring instructions. Suitable for normal 
fluorescent tabes or the new "Grolux" tubes for 
fish tanks and Indoor plants. Chokes are super- 
silent, mostly resin filled. Kit A — 15-20 w. 
19/8. Kit B— 30-40 w. 17/8. Kit O-fi0 w. 17/8. 
Kit D— 123 w, 22/-. Kit B— 05 w. 19/6. Kit 
M Kl is for 6 in., 9in. and lthn. miniature tubes 
19/6. Postage on Kits A and B 4/6 for one or two 
kits then 4/8 for each two kits ordered. Kits C, 
D and E 4/ 6 on llrst kit then S.'fl for each kit 
ordered. Kit MF1 3/6 on first lilt then 3/6 cm 
each two kits ordered. 



AUDIO SWITCH 

Want to open your garage 
door with a toot* Or 
close your curtains 
witb a whist let 
Or make any- 
thingobeyyour 
couimand 1 Then 
first you need an 
* Audio Switch- We 
offer complete kit, 
including 5 trans- 
istors, Veroboard 
panel, all the resistors and condensers and the 
relay with, diagrams* etc,, lor making 43/6 plus 
2/6 post and insurance. 




Wb ere postage is not definitely stated as an 
extra then orders over£3aro post free. Below 
£& add 2/9, Uumi-conductora add 1/- post. 
O ver£l post free. S.A.E, witb enquiries plaase. 



ELECTRONICS (CROYDON) LIMITED 

(Dept. P.W.} 102/3 TAM WORTH RD., CROYDON, SURREY (0pp. W. Croydon Siti,} 
also at 266 LONDON ROAD, CROYDON, SURREY S.A.E. with enquiries please 



197 



R.S.T. VALVE MAIL ORDER CO. 

BLACKWOOD HALL, 16a WELLFIELD ROAD, STREATHAM S.W.16 ZVZ 



Mon. — Sat. 9 a.m. 

— 5.45 p.m. 

Clos=d Sat. 1.30— 2.30 p.m. 

Open Daily to Callers 

Tel. 769-01 39,1649 



OA2 


0/3 


BBM6 


7/B 


003 


&/« 


BBJ6 


91- 


1A7 


7/S 


GBQ7J! 


7/- 


1D5 


7/- 


6BE7 


8/6 


1H5 


J/- 


OBBS 


6/S 


ILD5 


6/- 


6BS7 


167B 


1N5UT 


»l- 


BBWS 


14/- 


1R5 


6/8 


I5BW7 


14/- 


IS4 


5/- 


6C4 


B/9 


13a 


4/- 


6C5G 


4/- 


IT* 


8/- 


6C6 


3/9 


3A4 


bjh 


608G 


B/- 


3Q4 


8(6 


BCD6G 


88/- 


SQ5 


8/« 


6CB76 


8/9 


aat 


4(3 


6CW4 


13/- 


3V4 


Sffl 


BD6 


3/9 


BE4GT 


K/n 


6E5 


7/6 


6U4G 


*/- 


6P1 


9/- 


SV40 


«/- 


6F5S 


8/- 


5T3&T 


5/6 


6F6G 


4/- 


5Z4G 


fl/R 


6P8G 


4/6 


8/30L2 18/- 


6F11 


7/- 


BA7 


16/- 


6F13 


5/- 


8AS& 


1B/8 


BF14 


13/6 


6AC7 


u. 


6F23 


13/8 


6AK5 


4/e 


6P24 


12/6 


6AL5 


3/- 


SF25 


12/- 


0AM3 


2/8 


8F28 


11/6 


6AS16 


3/6 


60B 


2/6 


8AQ5 


fl/- 


GH6 


91- 


tJAS-l.I 


1ft/- 


6J6M 


6/6 


8AT6 


4/6 


BJ6G 


2/6 


6AC6 


fl/- 


6J6GT 


4/6 


SBSO 


Zl- 


6J6 


3/- 


6B4R 


1ft/- 


6J7M 


7/8 


BRA5 


S/- 


BJ7G 


4/9 


6BE5 


S/- 


6J7GT 


6/8 



6K6GT 


6/- 


737 


20/- 




BK7M 


fi/9 


7T4 


8/fl 




6K7G 


91- 


9BW6 


7f- 




BK7GT 


4/8 


10C1 


12/8 




8K8M 


8/8 


10O2 


12/8 




6K8G 


8(- 


10F1 


Rf- 




6K8GT 


11- 


] 0F3 


R/- 




BK23 


80/- 


10F9 


fl/9 




SL1 


9/6 


10F18 


9/- 




8L6G 


7/fl 


10L1 


B/- 




6L13 


n/- 


10LD11 15/- 




6Q7G 


«- 


10P13 


Ib/tf 




GQ7GT 


8)8 


11E3 


43/- 




G3A7M 


7/- 


12ATC 


4/0 




aaC7 


71- 


12AT7 


3/9 




6SG7 


61- 


12ATJ6 


S/fl 




6SH7 


8/3 


12AU7 


4/9 




63J7 


w- 


12AX7 


6/8 




BSK7GT 4/9 


19BA6 


8/- 




6SL7GX 4/S 


12BE8 


5/9 




6SST7GT 4/8 


I2C8GI 


4/8 




63137 


Bf. 


12E1 


17/6 




6U4GT 


W- 


12J5GT 


:'/(; 




6USG 


7/8 


12J7GT 


7/- 




6V63I 


«/- 


12K7GT 6/- 




6V6G 


4/8 


13KSGT 8/- 




6V6GT 


6/8 


12Q7GT 4/8 




8X4 


3/8 


12SA7 


6/3 




6XBG 


4/8 


128G7 


4/3 




BX5GT 


«/- 


12SH7 


3/- 




7B8 


11/8 


12SJ7 


3/9 




7B7 


7/6 


12SK7 


4/9 




7CS 


HI- 


123R7 


6/- 


i 


7C6 


15/- 


14117 


91- 




705 


3/- 


19AQ5 


ft/- 


1 


7H7 


«/8 


2GD1 


1(1/- 




7K7 


17/8 


20 F2 


14/- 


. 



20L1 17/- 
20F4 19/- 
2 OPS 18/- 
23A6 5/9 
25J.6GT 6/8 
2ST5 8/- 



2GZ4 


6/3 


26ZB 


11- 


25Z6 


W 


2SD7 


5/- 


30C1 


B/8 


30C15 


13/fi 


30CJ7 


14/- 


30C18 


13/6 


30F5 


14/- 


30FL1 


16/- 


30FT.12 16/- 


30FL1: 


13/6 


30L15 


lft/8 


30L17 


14/3 


MV1-2 


I2|- 


30F19 


13/- 


S0PL1 


15/- 


30PL13 15/- 


30PL14 16/- 


35A5 


12/6 


351,6 


Ii/H 


3oW4 


4/6 


3BZ3 


10/- 


35Z4GT 5/8 


3SZS 


5/8 


37 


5/- 


42 


6/- 


SOBS 


8/6 


50C5 


6/3 



S0CD6G31/- 
50L6GT 6/- 



7o 


7/- 


78 


6/- 


80 


5/- 


SSA3 


7/S 


150B2 


9/8 


150C4 


7/8 


801 


8/- 


307 


11- 


811 


36/- 


313 


7ft/- 


88BA 


13/8 


954 


4/6 


1625 


5/8 


4022AR 50/- 


57BS 


10/- 


7193 


8/- 


7475 


4/- 


AB1 


7/9 


ATP4 


8/3 


ATP5 


7/- 


ATP7 


5/6 


AU2 


80/- 


AU5 


7/8 


AZ1 


8/- 


AZ31 


9/8 


CBL31 


15/- 


CCH35 


21/- 


CL33 


80/- 


CY30 


16/3 


CYS1 


10/- 


UAC32 


11- 


DAF91 


4/- 


DAF96 


6/g 


DOC90 


11- 


DF33 


8/- 


DF70 


7/- 


DF91 


31- 


DFSB 


2/0 



DF9B 


B/O 


DH77 


4/6 


DK32 


7/9 


DK91 


5/6 


DK92 


8/- 


DK9B 


7/9 


DL66 


16/- 


DL92 


4/9 


DL93 


3/8 


DL94 


5/9 


DL93 


6/6 


LI U 6 


7/8 


UH70 


51- 


DY86 


s. 


DY87 


6/- 


i«>icc 


12/- 


EA50 


«- 


EABCSO 71- 


EAF42 


10/- 


EB41 


4/6 


EB91 


8/- 


!■: BCMS 


7/- 


EBC41 


9/9 


EBO90 


4/6 


EBF80 


11- 


EBF83 


8/8 


EBF89 


6/6 


EBL1 


14/- 


EBL21 


11/- 


EBL31 87/6 


EC90 


2/9 


KCIJSl 


3/9 


ECC82 


4/9 


ECC83 


6/3 


ECC84 


6/- 


B0065 


5/- 


V,t :C88 


11- 


ncrso 


0/6 



ECF82 


11- 


ECH21 18/8 


ECH35 


8/6 


ECH42 11/- 


ECM8I 


5/9 


ECH83 


8/- 


HCL*0 


71- 


ECL92 


11- 


ECM3 


10/8 


ECLSfi 


»/- 


ECI.MOO 




80/- 


EF9 


w- 


EF37A 


7/- 


EF39 


8/- 


l(l''41 


10/- 


EF50 


8/6 


EF30 


6/- 


EF8S 


6/6 


BFSB 


6/9 


EF89 


6/- 


EFB1 


8/6 


EF92 


8/6 


EF98 


10/- 


EF1S3 


6/6 


EF184 


6/8 


VAJA-l 


3/6 


ELS3 


12/8 


EL34 


10/8 


EL41 


10/- 


EM2 


10/- 


EL84 


4/9 


E1.90 


6/- 


EL95 


6/6 



ELMO 80/- 
EM34 85/- 
EM80 7/6 



EM81 7/9 
EU84 7/6 
E8U150B0/- 
ET51 7/6 



EY88 
EZ3a 
EZ40 
EZ41 
EZSO 
EZS1 
GZ30 
GZ32 
OZ34 
IRS 



ft 

4 .It! 
8/- 
10,'- 
5/6 

m 

10/- 
9/6 

11/- 
5/S 



KT36 17/8 
K'l-ol 18/0 
KT66 16/- 
KT81 35/- 
KT81 (7C5) 
15/- 
KT88 27/8 
KTW61 10/- 
KTZ41 6/- 
MIA 17/6 

.MLrJ B/- 

M3F4 10/- 

MU14 7/8 

MX40 18/8 

S37 17/8 

N7« 16/- 

N108 25/- 
NGT1 



SGTI 55/ 



OA2 
OC3 
0Z4 

PC86 



6/9 
5/- 
4/6 
11/6 
11/0 



PC97 8/9 
PGCS4 6/3 
PCC89 11/- 
PCC189 11/8 
PCF80 7/- 
PGFB2 6/- 
PCF84 8/- 
PCFSS 9/- 
PCF801 10/- 
FCF802 10/- 
PCF80513/6 
PCF806 18/8 
PCF80811/6 
FCL82 7/9 
POL 83 9/3 
PGL84 7/B 
PCL85 9/8 
PCL86 9/- 
PENA4 80/- 
PENB4 30/- 
FEN45 7/- 
PEN-46 S/fl 
PL36 10/- 



PM1 
PL82 
[■LS3 
PLS4 



PLSOO 16/ 

PX4 14/ 

PY33 9/1 

PY81 6H 
PY82 
PY83 



PY800 10/- 

PY801 10/- 

R8 7/6 

E19 7/9 



RGB/SOO 




80/- 


3130 


35/- 


8F4 


8/- 


3P41 


3/8 


si'ei 


3/8 


8TV280/80 




85/. 


siras 


19/6 


SUi:l5018/6 


T41 


15/- 


Til J 4 


10/- 


UK 


7/6 


U14 


7/8 


LIB 


36/- 


LT25 


13/8 


U28 


13/8 


U78 


3/B 


1 191 


13/- 


L"M1 


16/3 


U301 


16/3 


U403 


8/6 


L404 


11/9 


17801 


33/6 


UABC80 6/- 


UAF42 


10/3 


. 


S/S 


I Li(!Sl 


8/3 


1 ■ 117'80 


8/9 


ij'.r.ia 


7/3 


UCC84 


8/H 


1 'CC 35 


7/- 


rci«o 


3/6 


i ar.V2 


10/6 


101(81 


6/9 


UOL82 


8/- 


7 '01 S3 


10/- 


i:F4L 


10/- 



UF99 

UL41 

I Li4 

U1I80 

UU6 

LL7 

U179 

UY21 

UY41 

UY85 



7/6 
9/6 
71- 
6/- 
13/8 
13/B 
8/- 
9/6 

li- 
sts 



YMP4G 17/- 
VP4B 85/- 
VR105/30 

6/- 
VR 130/30 

6/- 

VTas 15/- 

VTSl 80/- 

VU111 7/8 

VU120 18/6 

VU508 35/- 

W81M 6/- 

X79 41/- 

XH1-5 5/- 

XP1-8 5/- 
X8G1-5 18/- 

Y63 7/6 



50/- 
19/- 
35/- 



Tiibea 
3EG1 
3FP7 
SCP1 
OV1526 40/- 
AOB13100/- 
VCR97 35/- 
VCRS17B 

46/- 
VCR517C 

40/- 



SPECIAL 24 HOUR SERVICE 

OBSOLETE TYPES A SPECIALITY 

QUOTATIONS FOR ANY VALVE NOT LISTED 

Postage fid. per valve. C.W.O. No C.O.D. 

Manufacturers and Export Inquiries Welcome 



Special 24 Hour 
Express Mail 
Order Service 



SETS OF VALVES 
DAF91, PF91. DK91. DL9'- 1 or DL94 

DAF9B, DF90, BK96, DL90 

BRAND NEW TRANSISTORS 



AC127 7/6 I OC25 11/. 

AF114 71- 0028 18/- 

AF115 71- OC35 11/8 

AF116 7/- 0C44 4/8 

AF117 SI- I 0O45 4/- 



OC71 
OC72 
OC75 
OC76 
OC77 



OCSi 4/- 

OOS:.iQ/pr 

13/8 

0C8:.d 4/- 

OCS'.J 8/- 



19/- the set 
87/8 the set 

OCS2D 6/- 

0083 B/- 

OC170 7/- 

OC171 8/- 

OC20O 7/8 



SEND S.A.E. FOR LIST OF 2,000 TYPES, 



<T8*K$IST88 

39% 



4hst Ptmat 
mm RAbio 




The Dewtron Eare Trap for portables 

Jc Boosts Radio 1, Luxsmbourg, Pops tie, 

^ Eliminates 'failing'. 

■it Extends battery life, 

i( Roplacen car aerial tor portable Beta. 

^t 7-day refund trial. £8 post free. 



ADD 




TO YOUR LISTENING.. 



with "SEW DIMENSIONS" effects amplifier. 
Adjustable echo, vibrato, tone, giving fabulous 
3-DimensIon music: 9Y battery model for radio, 
tape or player 8 fins., speaker 25/- extra. Gar 
version for 8 or 12V, positive or negative earth 
10 gns. with speaker. Add 5/- post and Insi) ranee. 

D.E.W. LTD., 
P.W., RISGWOOD ROAD, FERND0WK. DORSET 



TRADER SERVICE SHEETS 

4/- each plus postage. 

We can supply Trader Service Sheets 
and Manufacturers' Manuals for most makes 
and types of Radios, Tape Recorders and 
Televisions. 



Please complete order form below for your 
Service Sheet to be sent by return. To: 

OAKFIELD ENTERPRISES 

LIMITED 

30 CRAVEN STREET, STRAND 

LONDON WC2 



Make 


Model 


Radiol TV 





















1 968 List 
available at 2/- 
plus postage 



From 

Address . 



If list is required 
indicate with X 





enclose remittan ce of, 

(and a stamped addressed envelope) 

s.a.e. with enquiries please 

MAIL ORDER ONLY (July PW) 



1 *f\n V-r « 

WORLD-WIDE RECEPTION 



SHORT-WAVE 
KITS 




Famous for over 30 years for Short -Wave Equip- 
ment of quality, "ll.A.C." were the original 
suppliers of Short-Wave Receiver Kits for the 
amateur constructor. Over 10,000 satisfied 
customers — including Technical Colleges, Hos- 
pitals, Public Schools, E.U., Army. Hams, etc. 

IMPROVED 1)88 RANGE 
Ono -valve model "DX", complete kit — price 50/8 
(Postage and packing 3/6). 

Customer writes: — "Definitely the best one-valve 
S.W. Kit available at any price. America, and 
Australia received clearly at good volume." This 
kit contains all genuine short-wave components, 
drilled chasais, valve, accessories and full instruc- 
tions. Heady to assemble, and of course . as all our 
products— fully guaranteed. Full range of other 
S.W, kits still available, including the famous 
model "K" (recommeodei by radio clubs). All 
orders despatched by return. (Mail order only.) 
Send now for a descriptive catalogue, order form, 

"H.A.C." SHORT-WAVE PRODUCTS 
29 Old Bond Street, London W.1 



198 



Cleaning the plastic surface, both before the 
repair and afterwards, is best done with warm, soapy 
water. Beware of some detergents, which have a 
discolouring effect. Pure soap is recommended. Al- 
though some engineers favour the use of methylated 
spirit for practically every operation except cleaning 
their teeth, it is wise to avoid this or any other 
spirit when cabinets are lettered of over-painted in 
any way. No matter how carefully you try to clean 
around taboo sections, the capillary action of fluids 
may defeat you, and the ancillary paintwork smudge 
and smear. It may seem a little like cheating, but this 
writer has found the cleaning fluid supplied in the 
BIB kit for tape-head cleaning and the like to be 
ideal for intricate cleaning jobs on plastics, and 
quite harmless to paintwork, and cheap at 4s. 6d. a 
bottle. It can even be used to get the dirt from the 
milled edges of some of those ducky little knobs. 

Flutings, louvers, milled knobs and such can be 
nasty-looking dirt-traps. This is where the orange- 
stick and cotton-wool, or, again, one of BIB's clean- 
ing sticks comes into its own. If the brushing action 
is done away from the closed end of flutes or louvers, 
the accumulated dirt can be wiped away with these 
quite easily. 



ANTI-STATIC TREATMENT 

However clean her ladyship thinks she may be, 
some dust will be present in the atmosphere. Plastic 
cabinets attract it. Dimple or crackle finishes look 
very dull and unattractive when dust has gathered 
in the hollows, even quite minute amounts. The cure, 
after cleaning and drying, is to wipe over with an 
anti-static cloth, such as supplied by most retailers of 
gramophone records. Following this treatment with 
an overall wipe with one of the disc cleaning prepa- 
ration can leave a cabinet pristine and sparkling. 

This is all very fine, I hear some unfortunate say, 
but before I can begin to repair my cabinet I have 
to remove the knobs, perhaps the dials, and often 
most of the working parts inside. How to start going 
about it? 

Admittedly, the task is not always simple. Some 
knobs appear welded forever to their spindles, and 
are shaped so that a strong pull simply leaves one 
pinching air. With these, it can be helpful to apply 




Angled pliers are very useful for difficult Jobs such as removing 
reluctant knobs or gripping screws in awkward places. 

the old button-stick method of slotting a piece of 
thin, stiff card, sliding under the knob, then using 
two screwdrivers to apply a regular lifting movement 
from beneath its outer flanges. An assistant to help 
by holding the receiver down while you do this would 
be an asset. The use of two screwdrivers is to prevent 
a sideways twist that can so easily fracture the 
spindle grip of a fragile knob. Even better is a home- 
made lifter, consisting of a slotted piece of thin 
brass, that applies the pressure around more of the 



base of the knob. An invaluable item of the author's 
toolkit, often used for knob-lifting, is a long-nosed 
pliers with angled points. 

Fixing screws in cabinets are often one-shot 
devices. Coarse-threaded types are employed and 
removal may ruin the plastic thread in the hole. One 
remedy is to insert a piece of pvc sleeving in the 
screw hole to make a kind of plug, before re- 
assembly. It is a better system than building up the 
plastic with some form of putty, as it then becomes 
easier to dismantle next time. 




Not the best way to deal with portable radios. 

Cabinets themselves may be sprung together in 
sections. Many plastics lend themselves to this, and 
where a joint is obvious and no removal method 
indicated, it is best to press gingerly at each side of 
the joint to discover which of the two is the under- 
side section of the key (see diagram). Having found 
this, and applied even pressure, the cabinet will 
generally split along the seam with frightening ease. 
As with all other jobs on plastic cabinets, pursue 
this operation with the care you would take in 
handling women — be gentle, but firm! 

Removal of the chassis may entail disconnection 
of aerial rods, speaker or earphone sockets and 
sundry hardware. Do not overlook the basic chore 
— make a small drawing of connections, colour- 
codes of wires, etc. Trusting to memory has led many 
a good man into error. Some of the mini- jack sockets 
are secured with knurled rings which defy attack 
from outside the cabinet. With these, it is best to 
wedge a fine-bladed screwdriver in the knurled 
edge, then gently turn the whole socket from within 
to free the thread. Only a portion of a turn is re- 
quired, as a rule, and it is seldom necessary to dis- 
connect completely. Always take care, when handling 
these sockets, not to twist the connecting blades 
relative to each other, as short-circuits are not only 
disconcerting but can, in some instances, damage 
output transistors. Many of the earphone sockets are 
"shorting" types, with the connecting blade pushed 
away from a contact blade by insertion of the plug. 
With these, the common fault is weakening of the 
spring connection, always accelerated by mis- 
handling, so again— take care. 

That, if anything, has been the theme of this 
section. Take care of your cabinets as well as the 
works inside, to make a worthwhile job of radio 
repairs. 

TO BE CONTINUED 



199 



LETTERS 



The Editor does not necessarily endorse the views expressed by correspondents. 



Hoof tugging 

Your letter about leg pulling, by 
your letter you have not much 
experience on transistor as I have 
had OC45 specimen working at 
30MC/s AND more as these 
transistor seem to improve with age 
and it is up to the circuit confushoin 
that controls the operating poin. 
So think befor you critising I would 
like to add the same about OC44 
are the same mind you you have to 
have a transistor tester which put 
the transistor into oserlaision at 
they's FREQSIS your's sorry about 
bad spilling. — G. Williams (Wal~ 
thamstow, E.17). 

The above letter, printed as it was 
received, refers (we presume) to 
comments in The Amateur Bands, 
page 850, March issue. The author 
replies— "Cor" de G3JDG. 

Ham-band converter 

Regarding the 10-metre tran- 
sistorised converter (Feb. 1968). 
The following modification has 
been carried out with success 
enabling both 10 and 15 metre 
bands to be covered. 

A lOOpF twin-gang variable 
capacitor is substituted for VCla-b 
which, in the original circuit, was a 
20-25pF maximum. With the IOOpF 
gang, 10 metres will peak with this 
capacitor almost fully unmeshed, 
the tunable i.f. remaining as in the 
original article. Fifteen metres will 
peak with the new gang almost 
fully meshed and with the main 
receiver tuning over 4-5-4-95Mc/s. 
— L. Case (Lanes). 

Such a state 

"Solid State", what does it 
mean? This term nowadays preva- 
lent in our reading matter, be it 
editorial or advertising, it is beauti- 
fully engraved on to equipment 
obviously to proclaim something. 
Hi-Fi I can relate to high fidelity, 
but solid state — I am at a loss. Can 
anyone offer an acceptable ex- 
planation? — W, J. Toinlinson 
(London, E.17). 

Soldering saga , . . cont 

I have no wish to develop J. 
Macfarlane's 110V 75 W soldering 
iron into a saga. But — if the method 
of M. Francis (Cheltenham) is 
followed the 75W iron would be 
converted into a 150W iron. To 



achieve 75W with a series diode 
would require an additional series 
resistor of 68 £1 or so. Even with 
this resistor, the BY100 diode is 
over-run. — H. Bisplan (Morecambe t 
Lanes). 

Beginner's Licence 

I wholeheartedly endorse your 
comments in last month's Leader 
(June issue, page 95) re the 
Beginner's Licence. However, I 
suggest that the rot has already set 
in, and was probably instigated by 
the amateurs themselves. 

Why should Class B licensees be 
allowed on the two- metre band? 
If you subscribe to this idea, then 
why stop at two metres — why not 
let the Class B types down on to 
four metres? Many arguments 
could be put forward to support 
this. Then, once they are on four — 
why not ten metres? In allowing 
and indeed supporting this move, 
the radio amateur is surely guilty 
of sowing the seeds of an idea that 
there is need for greater laxity in 
the rules and regulations governing 
licences. 

It is too early to comment on the 
proposed plan for a true Beginner's 
Licence since nobody (well, only 
the late PMG) has any real idea of 
just what is involved. But with 
the present amateur's eagerness to 
allow all and sundry on to the 
two-metre band, one shudders to 
think what the real beginners will 
be allowed to do when they get 
going. — E. Mason (Cheyne Walk, 
London). 

Car radio interference 

With reference to "Your Ques- 
tions Answered" May, 1968 re 
Interference Suppression in car 
radios. 

What you have suggested is 
sound advice but I think you have 
overlooked one important factor, 
namely, aerial adjustment. Most 
modern car radios have a trimming 
screw and the usual method of ad- 
justing it is to — rotate the screw 
through the position for maximum 
volume and return again to the 
maximum position to ascertain 
that a peak has been found. Should 
you be unable to find a peak posi- 
tion, poor matching should be 
suspected and may be due to fitting 
of an inferior aerial. This will in- 
evitably result in reduced efficiency, 



and in poor reception of the more 
distant popular stations. It will also 
make the set more prone to 
interference. 

This advice is given with Motorola 
Radiomobile car radios and I can 
assure you that if these instructions 
are not carried out, interference is 
the result. — W. Doran (Bangor 
West, Co. Down, Northern Ireland). 

Advertisers' Rating 

In view of the number of letters 
concerning advertisers, could they 
be given "star" ratings like the 
AA do in assessing hotels? — 
J. Mirren (Bath, Somerset). 

{You mean the advts should read 
like—OC71 3s. ; AF115 4s. 6d.; bed 
and breakfast 15s. (J 7s. 6d. with 
integrated f.m. tuner); BC108 3s. 
etc.] — Ed. 

The bob drain 

Mr. McLaren, Letters May, 
writes of the fortunes being made 
from Is. postal orders sent in reply 
to adverts. 

We advertise on this basis be- 
cause we find that 95 % of requests 
for literature do not result in 
orders. If no charge was made the 
costs of printing, postage and 
advertising would have to be paid 
solely by those ordering goods, 
with a consequent increase in 
prices. 

I can assure Mr. McLaren that 
Is. is a small amount towards the 
handling costs of an inquiry, if all 
costs are considered. 

This is in no way to condone 
deliberate fraud of this type, but 
before condemning try a little 
simple arithmetic, and also remem- 
ber that mistakes can happen with 
regard to enclosures omitted. — 
R. G. Silson (near Station, Tring, 
Herts.) 

Twenty-two sets 

As you are aware there has been 
a release of Ministry 22 sets. 

I have a manual on these sets 
showing heater values, circuits, 
resistor and capacitor values to- 
gether with technical descriptions. 
No doubt some of your readers 
have bought these sets, so if there 
is any query they have, please con- 
tact me and I will try and answer 
their questions, or supply informa- 
tion. — P. James (27 Herbert Road* 
Sompting, Lancing, Sussex). 



200 




EWMAR 

Dept PW18 

30/32.SHUDEHILL MANCHESTER 4. 

Telephone.(061) 832 7710 

Also at: 15 WHITECHAPEL, LIVERPOOL (Near Lord Street) 

FREE GIFT OFFER 

OF A BRAND NEW WORLD FAMOUS E.M.I. FISK SOLARIS COPE 
VALUE £2.2,0 WITH EVERY ORDER VALUE £5 AND OVER. THIS 
UNIQUE INSTRUMENT WHICH IS A BOON TO SHORTWAVE LISTEN- 
ERS CLEARLY SHOWS THE AREAS OF DAYLIGHT AND DARKNESS 

ALL OVER THE EARTH AT ANY GIVEN HOUR, 

MINI -MOTORS ::'. I ■ -l-.iV. -).'rc;<i >ji. r.ii-.-ii it;-: miii:-r;iri!:i; r;u< el', "I arm "■ fll ■ x 

Via x l 2 ' 5 in.)8/ll. Medium (1 v »;, x 1 'in.) 3/9. P. <t 1». 3d, * 

GENUINE DIAMOND STYLUS at 7/Ujjln? fid" P.P. Available as replacements for 
the following popular types only at present: BSR TC8LP— BSE TC8 STEREO— 
BSR TCS LP/BTERE0— COLEARO STUDIO «0» LP/RONETTE— GAEKABD GU8 
LP— ACOS BP8S/87 LP— KONETTE BF40/LF— GARRARD GC2 LP, All these tvpes 
■ '- BappMre. Value at i.nlv 3/11 each. 



now available J 



SPEAKERS, lain, mum! hiirh qunlii> T ; r i - : - ■ , fi;'..-d i»,,i fn ime,6 watts, in 3 J] fir 
IBB. 35/-, P.P. 3/0, ROUND 12in. K. * A. 3 B, 25/6, i'.I'. S.ol. Minv other speakers 
available. Sin. 3 or IS B, 39/8. lOin, 3 or la B. 35/6. 10 ™u bass speaker by F.M.I. 
lain, x Bin. 13 B, 39/11. With double tweeter. Very sensitive, 79/11. P, & P. 3/6. 
TWEETER. :-'; ii.. Itl.iik plastic cone, Square Irmit, E..V.1. 3 Q , 12/6, plus 1 Id P. & P. 



MICROPHONES. LAPEL/HAHD MIKE — liin. dia. Lapel Ulip, ideal for tape record- 

ing. Very sensitive, 7/6. P. * P. U-. Similar but slick type AMA, 14/8. 

CRYSTAL HAND MIKE. Robust and sensitive. Cream plastic ease. Just the tiling 

tor tape recorders, 8/8. [■. & P. 1/6. Similar with built-in -Mmi, 10/6, 

STUDIO CRYSTAL MIKE. Profes.-d.nuii. o-irii-dirt-riiiii.il, providing features usually 

only available at many times the price. Sensitivity— sod B. Response — BO-12,000 

c.p.a. Black Plastic with punched ebromium case, swivels, stand-holder and shielded 

cable. Only 48/-, P. & P. a/-. The stand below at-, t-hu mike (a* well as many others) 

ACOS MIC 40— World famous Desk Mike. 16/6 plus P. A P. 1/3. 

ACOS MIC 45— Splendid Curved Hand Clrip Crvaial Mike, 18/3 pins P. * P. 1/6 

ACOS MIC 60— "Suck" Tvpe Crystal Mike, 21/3 plus P. A P. 1<6. 

ACOS 39-1— High Qualitv Stick Mike. High Impedance, 33/- plus P. A P. 1/6. 

ACOS ROUND tin .,,-,! \ijk._- insert. I:.in. dia.. 7/6, P. Lt P. ild, 

TELESCOPIC FLOOR STAND, HEAVY BASE. Standard thread, est, to 41t. 7in. 

49/6. Carnage ami Packing 4-Ti. D':<k -tnii.l ic-stkk r»ik.-=. 7/6. 



SIREN MODULES. I'lnr.'ipsulated solid itatE circuit. Only requires 30 speaker, switch 
and battery (9v.) to complete. Give,' screaming siren note. Special halt price ofler. 
I.i-i 25/-, Our pr ice 12/6, p.p. 1/-. Make ideal burglar alarm or warning system. 



INTER-COMMS— DE-LUXE MODEL 2-WAY. HlgfcU BefeBt, safe. Ideal BABY 
ALARM. Transistorised. Remote station can call master with latter switched oH. 
Very easily litte.t. Complete with battery, cable and plugs, 77/6, P. & P. 2/fi. 
We can also offer a limited supply .;;' a ii.i-:,.k-l made ltv l.'tiilips to retail at gns. — 
l/.ud and nicur Cur Price 59/11, P. ,v P. -j;- . Ctanpli-te «in, nableaml i ..;.-. standard 
ballerv 3/6 extra. This is a high quality product and fully guaranteed, 
AMPLDJEER. Compact for use in mains portable grams 6} x 2} x olin., vol, and tone 
controls attached by fly lea ds, ov er -2 watt? output. 59/6. P. * P. 4/6. 
4 TRANSISTOE 3W AMPLIFIES. Slje 2[ x2f iljin,, 3, a or 15Q output, 9 volt 
halt fry operated. Highly sensitive. Price ile»s battery) 68/6. P. 4: P. 1/6. 



GAEEAED RECORD PLAYEE DECKS 
Model 2000, Mono oartridge ..£88 
Model 3000, Stereo cartridge 410 10 

ATGO Mk. n £15 9 

A 70 Mk, n Laboratory Series £17 17 
SP25 Mk. H Heavy Turntable £18 19 
B.S.R. Type GU7 £5 5 0, UA16 £B IS 
Cartridges lor thse players: 
Mono . , . , . , 16 

Stereo £1 10 



Carriage an 1 PackiuL- 
Garrard Plinths 
Perspox Covers . , 
1025 less cartridge 
AP75 less cartridge 
SI. So less cartridge 
SL55 less cartridge 



7/8 extra. 
£3 16 
£3 10 11 
£8 10 6 
£28 19 6 
£14 10 
£12 



CAR RADIOS. Pushbutton, all transistor, two wave, fits most ears, absolutely 

'■'■'in] i:b\ rV,. ; - iv >■! n.-cnti~e earllj. I'n'.L'l or lnsiiual i k. Free Aerial. 121 gns. 

Also available manually operated, otherwise as above, gas. 

!'■ A P. on each of I he above 5/- extra. Doth excellent value and fully guaranteed. 



MAGNAVOX "SaS" TAPE DECKS. LATEST MODELS. WORLD FAMOUS. 
13; x 11 x oiin. below board. V&t a00/B00V 50 cycles A-C. 3 speed, digit counter, 
piano key control-, Tin. reels Every nmdern feature. Speeds li, 3j and 71 i.p.s. 
With 1 track Marriott heads. £13.9.8, P, & P. 10./-. Price includes Free Ultt. 



TAPE RECOEDEB. Magnificent portable solid state, battery tape recorder. The best 
yet. 2 speeds, capstan drive, as good for music as. speech, 31n. reels. Absolutely 
: ii'i'ku- with remote control, mike, tape, batteries, etc. £10.19.6. P. « P. 5/., 
PICK-UP CARTRIDGE REPLACEMENTS Standard Fitting lor all Record Players!, 
ACOS GP/67-2 MONO 15/-. ACOS (;l',7;{--_> STEBKO 30/-. AC-OS RP 91.1 MONO- 
IiK-I.IXESl/-. BOKOTOHKSTACKRAMiCSTERIiu 37/6, SOiOTuMi? Til AC 
CEKAMIC-58/e. P. A P. 9d. 
Finest Quality British made MYLAR Recording Tape, Fully Guaranteed, In Cartons. 

:ii» !.V>a. Mess.iS.' 3/11 5^ in. 1 villi Ml . l/«i; Play 15/6 

3iii. 240ft. Message 6/6 Tin. 1800ft. Long Play 23/- 



siu . liOOit. Standard Play 10/3 

,v;in. 850ft. Standard Plav 13/- 

71u 1-Jin.ift Standard Plav 16/3 

6in . 900ft. Long Play 13/3 



Sin, 1-20HT1 . Iir.ubie Plav . . . 15/6 

5|in lsuilft. Double Plav 83/- 

7in. 240011. Double Play 87/- 

T^jaderUpe various colours , , , , 3/- 



& P, 1/- per reel. Four reels and over post paid. Tape splicer 17/6 plus P. A P. 1/-. 
POCKET MULTI-TEST METER. 1000O per volt. Volts 10 so ■>;,.> oon, 1000 A.C. 
and B.C. Current: 0-1 -100-50 OmA. Resistance; O-lDOka. Complete with test 
prods, instructions. 37/6. P. & P. 1/fl, De-Luxe model, large scale 55/11 plus P.P. 1/6. 
MULTTTESTEE — Pocket sue: with built, in meter protection. Wide angle, jewelled 
meter movemei it . 30,000 Q per volt D,C. 10,000 per volt A.C. • 19 ranges — 5,25 
00,250, 500,2300 volts D.C, 0, 10, 50, 100, 500, 1000 volts A.C. • 0-50uA-2-5mA- 
250mA D.C. • O-fiOOOO-6 mcgnhim. lOfifLi'-O'DOl mi'd. • —20 to + 23dB. 
Mirror Scale, Complete In cloth-Uned leather case with carry strap and test leads. 
K\ceptional valur at £4.11.6 (P. A P. 3/6), 



TRANSISTORS: snunc popular tvpus Irom our range: yt-14 and Oc-ir. 3/B each. 

OC71 2/9, OC72 3/8. OC81 and OCS1U 3/- each. Ocllia 3/9. OC170 3/6, AF117 4/-. 

OC26 7/6. GETS 5/9. rteneral puriiuse i.\]jprox. O071) 1/- each. 

NEW HIGH PEE8UENCY TEANSISTORS. Sinclair HT140 4/-; ST141 8/-, both 

capable of operating up to 70(1 Mc/s, ALSO -MAT100 7/9. M AT101 8/6. MATl'iO 7/9. 

MATl-il 8/6. A DTI 40 15/-. 

All Transistors postage 6d. up to 3. Over 12 sent P, * P, paid. 



Xcw delivery of BAKER SPEAKERS at special low price. Heaw dutv 23 watt bass 
speaker "Group 25", £6.3.0. High Fidel ltv 15 watt Speaker 15-13,000 ops ■■.Stalwart." 
£6.6.8. 



TERMS. Cash with order. >o C.O.D. Orders total £5 and over sent carriage paid 
(excepting record player decks where carriage is shown). Guaranteed money refunded 
if goods returned perfect within 7 days of despatch. 



TECHNICAL 
TRAINING 

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tice of valve and transistor circuits, and servicing work while 
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201 



JOHN'S RADIO OLD CO-OP. WHITEHALL ROAD. DRIGHLINGTON. BRADFORD 




LARGE QUANTITY OP SARAH V.H.P. TRANS/ 

RECEIVERS 

AVAILABLE FOR IMMEDIATE EXPORT 

Genera {Informal I is is. This set Is normally carried in tbe 
life Jacket of Airmen. It is a complete miniature light- 
weight radio Trans/Receiver, which Is nse<i to give ft 
Beacon plus two "way speech communication in the event 
of finding tlieiiiHelvcs in the sea. It comprises a Trans- 
mitter-Receiver, « speech tinit, s coding unit and ft power 
supply eitherBftttery or Transistor, These three items are 
permanently interconnected and all unite are completely 
sealed and water tight using a combined speaker/mlke. 
Press to talk or listen buttons, (old up aerial, a total of 
three valves are used, power required 6-3 volte LT 
SO volts and 485 volte D.C, HT, Frequency 243Mc/s. 
Transmitter output pulse power, ligation 15 watte, Talk 
3 watte. SUPPLIED IN MAKER'S BOXES in Grade 1 
condition singly at 45/-, post !•:'■ with circuit. New 
batteries If available 7/8 each. 



B40MKIII TRANSRECEIVERS 

We have a few of these V,H.F. 12 valve transreceivcrs 
operating on 3 a witched channels between OOMc/a- 
SSMc/s complete with all 6 crystals, headphones, mike, 
mobile aerial and dipole aerial, all connectors plus alloy 
tripod for mounting the set on. Power input 12V D.C., 
TX output 3 watts, internal speaker (all valves BG7), 
All air tested O.K.. Supplied in good grade 2 condition at 
£ 10.0.0. each, earr. SO/-, Also available tn matched pairs 
£25 per pair, corr, HO/- tested 



TRANS/RECEIVER TWO TWO 
This Is out of the latest releases by the govt, of an ex- 
tremely recent R/T set covering 2-SMe/s in two switched 
bands, containing 13 valves (3 ELSKs in TX output) 
which can be used for mor» c CW or R/T, Also has netting 
trimmer, BFO, RF and AF controls, switched meter for 
checking all parts of set. size 17 x 8 i 12in, Power re- 
(mired LT 12V D.C., HT 323V D.C. Supplied brand new 
and boxed with headphones and mike also two spare 
valves and circuit of Bet. Few only at £5.10.0., earr. 30/-. 
New piug in power supply made bv us for cither 12V D.C 
input 48,10,0 or 200/260V A.C. £3.17.6. 




FAMOUS ARMY SHORT-WAVE TRANSRECEIVER 
MK.III 
This set Is made up of 3 separate units: (1) a two valve 
amplifier using a 6V6 output valve; (2) (some only, not 
built in the very latest models) a V.H.F. tranareceiver 
covering 229-241 Mc/s using 4 valves: (3) the mainshort 
wavetransmitter/receivercovcring in two switched bands, 
just below 3 Me/s— Ij Mc/« and 4i Mc/s-8 Mc/s (approx, 
180-37 -8 metres) using 9 valves. For R.T., C.W. and 
M.O.W. The receiver is superhetrodyne having I R.F. 



stage, frequency changer, two I, P. (485 Kefs) signal 
detector, A.V.C. and output s'sagc. A B.F.O. included 
lor O.W. or single aide-band reception . T.X. output valve 
807 other valves octal bases, Manv extras, e.g. netting 
switch, quick flick dial settings, squelch etc. Power re- 
quirements LT 12 volts, HT receiver 275 volts D.C. 
HT transmitter 500 volte D.C, sine approx. 17* X 7 J x 
lltns. Every set supplied in new or as new oondltlon in 
carton wttb book Including circuits, only £4,10,0, or 
Grade 2 sUgbtlv used 50/-. Grade 3, lined but oatagme, 
35/-. Carr. ALL 15/-. WE MilKE A MAINS 200/250 
VOLT POTTER UNIT in louvred metal case to plug 
direct Into set power socket to run (1) receiver, 70/-, post 
6/-. (2) TX and KX , £6.10.0. post 7/6. (3) 13 volt D.C 
P.U. (original), FAIR CONDITION, 40/-, Can. 67-. A 
charge of 10/- to unpack and test the receiver of these 
sets is made only if requested. Headphones and Mike 15/-, 
new and boxed. 




L : 

VMS. TBANSRECEIVER MK. I/I 
This is a modern self contaii.cd tunable T.HJ. low 
powered frequency modulated transrecelver for R.T. 
communication up to 8—10 miles. Made for the Ministry 
of Supply at an extremely high cost by well known 
British makers, using 15 midget B,G. 7 valves, receiver 
Incorporating R.F. amplifier. Double superhet and A.F.C 
Blow motion tuning with the d ,al calibrated in 41 chan- 
nels each 200 Kefs apart. The frequency covered is 
30 Mc/s-48 Mc/s, Also has built-in Crystal calibrator 
which gives pips to coincide w.th marks on the tuning 
dial. Power required LT 4* volts, HT ISO volte, tapped at 
90 volts for receiver. Every set supplied complete with 
valves and crystals, New in carton, complete with 
adjustable whip acria), and circuit . Price £4.10.0,. carriage 
10/-. 



BI-PAK SEMICONDUCTORS 

8 RADNOR HOUSE, 93-97 REGENT STREET, 
LONDON, W.I 



AO107 


3/6 


AC126-7-8 . 


2/8 


AF1 18-117 


3/6 


AF1S9 


. 10/- 


A 1.102 


. 15/- 


BC107-A-9 


, 6/- 


BFY50-51-52 .. 


7/8 


B9V26-7 


3/6 


BSY28-0 


4/6 


BSY9S-90A . , . . 


4/6 


U( -i-2--23 


W- 


(X ■20-35 


. 6/- 


(><">tV9 


7/6 


OC44-45 


. 1/9 


OC71-S1 


. 1/6 


OC72-76 . 


2/6 


Ot'SlD-SSD ... 


2/3 


OC82 


2/6 


OC140 


. 67- 


OC170 


. 2/6 


OC171 


3/8 




7/8 


ORPi2-ao 


. 8/6 


OOP71 


8/6 






O A47 


21- 


OA70 .... 


. 1/3 


OA79 


. 1/9 


OA81-S5 


1/6 


OA91 


1/3 


OA05 


1/9 


OA200 


. 31- 




3/6 




. 5/- 


2X706 


. 8/8 


2X708 


. 5/- 


2X2180 


. 15/- 




. IB/- 


2N2712 


, 5/8 


2N2926 


. 2/6 


MAT100 


. a/- 


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202 




PART THREE 



AMPLIFIERS 



IN Part 1 of this series I mentioned that the 
amplifier was the strongest link in the reproduc- 
ing chain. This is probably due to the fact that 
an extremely accurate assessment of the perform- 
ance of an amplifier can be made, as the function 
of an amplifier is purely electrical. There are no 
mechanical considerations, such as with pick-ups or 
loudspeakers. Amplifiers are the power producing 
link in the chain and must be very efficient. They 
must also be distortion free in their signal handling 
capacity. With modern amplifier circuit design this 
sort of performance is not uncommon. 

The Choice 

Valve or transistor? This is the question that 
most aspiring high fidelity sound enthusiasts ask. 
The answer really depends on how much you are 
prepared to spend on this vital but superlative link. 
I firmly believe that unless you are professional, or 
prepared to pay the sort of price a professional 
expects to pay, you would be better off with a valve 
amplifier. Up to the present, transistor amplifiers 
have not turned out quite as we were led to believe. 
The term "transistor sound" implies an insult rather 
than merely a performance description. The main 
point is that there should be no such thing as 
"transistor" or any other sound, just the original 
sound actually as it occurred. 

Design of valve amplifiers and understanding of 
valve parameters has reached such a stage that 
harmonic distortion can be brought down to the 
0- 1 % region, which is negligible. It is true that 
this can also be achieved with transistor amplifiers. 
However, it is achieved with the application of 
greater amounts of negative feedback, meaning less 
output power for a circuit giving equivalent gain 
without feedback. One characteristic of transistor 



nn 



1 f — i 



(a) 



<b) 



JU 




CO 



<d) 



Fig, 3: Some examples of square wave performance: (a) very 
good, (b) reasonably good, (c) fair, (d) poor. 



to hi-fi 



IAIN SMITH 

amplifiers, not prevalent in valve amplifiers of com- 
parable cost, is "crossover distortion" due to the 
fact that transistor amplifiers usually have outputs 
in Class B operation. This distortion cannot be 
reduced with negative feedback. 

To sum up this argument on valves or transistors 
I would say that transistor performance can equal 
valve performance in all aspects but the cost is far 
greater at present. No doubt this situation will 
rapidly change. Now let us examine amplifiers in 
general. 

Good quality amplifiers suitable for high fidelity 
use will have a frequency response from 20c/s to 
20,000c/s ±IdB. The ±ldB assures an even flat 
response. Response curves for sound performance 
are usually plotted as frequency, to a logarithmic 
scale, against decibels, which is the sound output. 
The reference of OdB is usually taken as l,000c/s 
and any variation from the straight line of this 
reference is quoted as plus or minus the number of 
decibels (dB) variation. Why is frequency plotted 
as a logarithmic scale? This is in order to compress 
the frequency range so that the whole spectrum can 
be fitted on to one graph. Besides having a wide 
frequency response amplifiers should have outputs 
with a low harmonic distortion output in the region 
of 0T% to 0-5%. Square wave response is impor- 
tant and there should be little or no traces of over- 
shoot, ringing or fall-off in the output. Figure 3 
shows some examples of good and bad square wave 
response. 

Valve amplifiers, because of the high impedance 
loading necessary for valves, have an output or 
matching transformer. The primary winding of this 
transformer is wound to the impedance value neces- 
sary for correct loading of the valve and the 
secondary winding is wound to the same impedance 
as that of the speaker coil. The turns ratio is deter- 
mined by the relationship Z primary = n 2 Z 
secondary where n is the number of turns of the 
primary winding. 

Output Transformer 

The output transformer is, perhaps, the most 
important single component in a valve amplifier. 
Unless carefully designed it can cause the response 
curve to drop in the upper frequencies. This is 
because XL = 2n-fL where XL is the winding 
reactance, f is the frequency and L is the winding 
inductance. The bigger XL is, the bigger is the 
impedance and the bigger is the volts drop across 
the winding. The output transformer must also be 
conservatively rated so that it is "man enough for 
the job". If the amplifier is rated at the maximum 



203 



output of 15 watts then the transformer should be 
rated, at least, to this value. If the transformer is 
under rated then saturation of the core will occur, 
causing "clipping" of the waveform and hence dis- 
tortion. This is particularly so at the low 
frequency end of the range. Transistor amplifiers, 
due to the low impedance loading necessary, can be 
designed to function with a transformerless output 
stage, an obvious advantage. 



Noise and Hum 

A problem more prevalent with valve amplifiers 
is hum and noise. Transistor amplifiers tend to give 
some hiss and crackle, known as noise; but they 
give virtually no hum. Valve amplifiers usually hum 
because of the a.c. heater supply. You have pro- 
bably seen in specifications that hum and noise is 
— 60dB at full power. This means that with the 
amplifier delivering full power the hum and noise 
level is 60 decibels less in intensity. In other words, 
the signal is 1,000 times greater than the hum and 
noise. This is referred to as the signal-to-noise ratio 
and a good amplifier will be in the region of — 60dB. 

Earlier, negative feedback was mentioned as a 
cure for harmonic distortion. Quite simply, negative 
feedback means taking a portion of the output 
signal and feeding it back to one of the earlier 
stages in phase opposition to the main signal. This 
cancels, to some extent, harmonics. There is another 
way of reducing harmonics by connecting output 
valves or transistors in "push-pull" operation. 
Figure 4 shows two valves connected in this fashion. 
The previous stage is a phase splitter and inverter 
stage, and feeds each output valve with half of the 
output signal, one valve handling the positive half, 
the other handling the negative half. By feeding 
these two halves into a primary winding of a trans- 




former, which is centre tapped, a continuous output 
signal can be obtained. The fact that the signal is 
split and "pushed and pulled" in this way tends to 
cancel all even harmonics, thereby greatly reducing 
harmonic distortion. Amplifiers with output stages 
not connected in push-pull are termed "single 
ended" and are not really of a high enough quality 
for us to consider here. 

Sensitivity 

Now let us switch our attention from the output 
to the input and the "sensitivity" of our amplifier. 
Briefly, sensitivity is the minimum signal required 
to develop full output power. Our signal source, 
therefore, must be able to develop this magnitude 
of signal if we are to obtain maximum power. This 
is particularly important with low-gain, low-power 
amplifiers where power reserve is small. If your 
signal is too small to drive your main power ampli- 
fier then you need what is known as a pre-amplifier. 
This is a small voltage amplifier, connected between 
the signal source and the main amplifier input, to 
"boost" the signal voltage to the required magnitude. 
At what power should your amplifier be rated? 
The answer really depends on the area to be 
covered by the sound. For outside use, 50 to 100 
watts is reasonable, but the majority of domestic 
requirements will be satisfied by 10 watts, which will 
give adequate reserve. 

Amplifiers can be examined in great technical 
detail but this is not meant to be a technical article, 
just an advisory one. Let us, therefore, summarise 
as follows: 

1, On a cost/quality basis a valve amplifier is 

probably a better buy. 

The frequency response should be 20c/s to 

20,000c/s. 

The harmonic distortion should be 0-1% to 

0-5%. 

Hum and noise should be in the region of 

— 60dB. 

Square wave response should be good. 

The output transformer should be conser- 
vatively rated. 

The output stage should preferably be in 

"push-pull" mode. 

The input signal should match the sensitivity 

of the amplifier. 

to be continued 



2. 



S. 



Fig. 4: A typical push- pu ft output stage of an audio amp fitter. 
204 



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A Guide to Amateur Radio (RSGB) 6/9 

the best way to get acquainted with Amateur Radio 

Radio Amateurs' Examination Manual (RSGB) 5/9 

covers the whole syllabus of the Radio Amateurs' 
Examination set by City and Guilds 

Radio Data Reference Book (RSGB) 14/- 

provides concisely virtually all information and 
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Service Valve and Semiconductor 

Equivalents (RSGB) 5/6 

equivalents of most Service valves and 
semiconductors 

Morse Code for Radio Amateurs (RSGB) 2/- 

a booklet to help you pass the GPO Morse Test 

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an American publication which can break you 
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a valuable handbook for the newcomer 

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the theory and construction of all the aerials and 
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Name 

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205 




PEAK-SOUND 8+8W. TRANSISTOR STEREO AMPLIFIER 

IN KIT FORM 

Build tbi» lor £9 10 f4/8 post). Power Pack Kit £3.10.0 (4/- post. Cabinet dee illustration: 50/- post paid or H4.1B.0 
the three Items post paid. Parts List Booklet ani lull details 1/8 :!ree with kit), A.E.I. CircuU ol 14 Transistors: SW Dor 
Channel into 3 to 15 ohmp Speaker. 50mV input Ceramie, Cryatal Cartridge. Radio Tuner or Output trom.Taue Recorder 
mar bo used. BO to 20 000 Hz — 3dB. Neg, Feed Back lBdB. 12fn. x 3in. nifiti ■ 8in. Cabinet, Cir-Kit Board Construction 
Bass, Treble and Vol. Controls, tor A.C. mains ol 200-B50V. Bass Cut and Lilt; Treble Cat and Lift, Fully bnilt into cabinet 
£17 post paid. Delivery by return post. 



TRAtfSISTOB POWER OUTPUT STAGE on P.C. Board (with diagram). 5|in.s'2in. X 
IJIn. high. Tdstiirl and working. OC71. OCS1D and tS x 0081 and Heat Sinks. With 
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Post paid.oK Log Pot + Switch 4'-. Sin. x *2iin. 35 oliin. Speaker 16/6. 

NEW RANGE GARRARD ATJTOCHANGEBS. All Carr. Pd. and without cartridge 
except type 3000 (stereo) and B3R VASS (raonol. 1025— £10.2.8; 3W8 -£10.10.0; 
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1JW MAINS GRAMOPHONE AMPL. EZS0, ECL82. O.P. Transformer (3 ohm) 
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aeparate but wired to chassis, 4in, X "JJin. x 4Jin. over valves. 65/- post paid inehiding 
8 Jin. Speaker. (52/6 less speaker.) 



NEW P.M. TUNER. Range 87 to 107 HE?. Attrac- 
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Sutkct. Valves 6BP.7; 12AXT; 

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UL84 
UY41 

U YS5 



5/9 
6/6 
5/3 



Postage on 1 valve 9ii. extra. On a yalvos or more, 
postage fld* per valve extra. Any parcel insured against 
damage in transit 3d. extra. Office address, no callers 

GERALD BERNARD 

83 OSBALDESTON ROAD 
STOKE NEWINGTON 

LONDON, N.16 

MOBILE S.W. LISTENERS 



The most evident mobile All-Band Whip on the market. 
GOILH FOR ALL BANDS. Complete with one coll 

fie.rr.e, plus 3/6. Extra coil* £3.i7,e, plus s/-. 

3?ew Sprung Extension safeguards your whip from damage 

From ifaditiff amateur radio uteres ttr direct from the 

man ufaiiurers : 

HALSON ELECTRICAL SERVICES 
Dover Road, off Anidell Road, Blackpool 



art types of 

TRANSISTOR €QUtPM€NT 



The Ideal, economical and safe way of running Tran- 
sistor Radios, Record Players. Tape Recorders, Ampli- 
fiers etc. from A.C. Main?, All units are completely 
isolated from mains by double wound transformer 
ensuring 100% safety. 

PLUS-3 

MAINS UNIT 

Provides three separate 
switched output voltages 
6v., 7£v. and 9v. DC. At- 
tractive case with indica- 
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output socket, plus arid lead. 
Size 4i t.i;i2; in. 




57/6 



P.1P.2/6 



(Extra lead with DIN plug lor Cassette Recorders 7/6) 

POWER PLUS 

MAINS UNIT 

for Cassette Tape Recor- 
ders using 7iv. Complete 
with DIN plug for recorder 
power socket. Can also be 
supplied for a B-volt out- 
put complete with suit- 
able plug. (Please state 
matte, model and voltage 
required.) 




£4.15.0 



MAINS UNIT for FI-C0RD 202A 
TAPE RECORDER p. & p. s/-. 

MAJOR POWER PLUS 

MAINS UNITS 

For single outputs, 9», 6v, 311/6. P.&P.2/6, 
For two separate outputs, Sv -j- 9v, 
6v -f. 6v. 42/6. P. A P. 2/6. 
(Please state outputs requited). 

R.C.S. PRODUCTS (RADIO) LTD. 

[0 apt. P.W.). 31 Oliviu Road, London, £.17 





206 



CLUB 
SPOT 



Allerton & District j 

NO. 19 SCOUT RADIO T 

HOBBIES CLUB z n 

R 



THE club came into being three years ago, and was 
founded by Mr, I. G. Rees (G3VKZ), The club 
has a number of licensed members; Tony 
(G3WRY), Andy (G3PKW), Ken (G3WCS) and Ivor 
(G3VKZ). The club also boasts a group of keen 
s.w.l's who are always willing to help out at contests 
etc., by logging, while those who cannot read c.w. 
are quite content to make tea. The tea makers, how- 
ever, plan to graduate to a callsign of their own, and 
the club offers every assistance. At every meeting a 
half -hour Morse class is taken by one of the licensed 
members, and every other week talks and demon- 
strations are given by G3VKZ on basic radio theory. 
Thus it is hoped that in time all the s.w.l's will hold 
tickets of their own. One member has already taken 
the R.A.E. and Peter, harmonic of G3WRY, will be 
doing so as soon as school exams permit. 

The members are fortunate in having a really 
good QTH, since meetings are held in the Scout 
H.Q. in Church Road, Woolton. Woolton is the 
highest point in Liverpool, and rises to 350ft. a.s.l. 
This QTH is excellent for v.h.f. and u.h.f. as contacts 
on 4 metres have revealed. During the recent Jam- 





-*. Morse practice for two 
s.w.l's trying to reach that 
magic figure of twelve 
words per minute. 
G3VKZ giving an informal 
lecture on how and why 
transmitters tick. > 




Three of the licensed members caught by the camera. Left to 
right: Ken (G3WCS), Lauerence (G3XGL), Tony (G3WRY), 

boree On The Air, contacts on the h.f. bands inclu- 
ded Australia and Japan, while on topband contacts 
were also good despite bad conditions. The antennas 
used for J.O.T.A. were a half-wave for 160, and 
dipoles for the h.f, bands. Unfortunately, the anten- 
nas cannot be left erected due to vandalism. 

Besides operating from Woolton, the club also 
operates /A and /P such as in the recent Scout 
Challenge, when all members and equipment had to 
be transported to Maghull, north of Liverpool. 

Members come from all walks of life and most are 
still in the process of receiving education of one sort 
or another. The club can obtain from within vir- 
tually all its needs either free or at trade prices. It 
even has its own photographer who was duly con- 
verted and now hopes to get his ticket soon. Licensed 
members can be heard on the air fairly regularly 
and when more members are licensed regular skeds 
are planned. 

Future plans for the club include entry into as 
many contests as possible, and a DX-pedition to a 
"rare" County operating on topband and 4 metres. 
AH prospective members are very welcome and a 

fair proportion of 
r™ members are not actu- 

ally scouts, but are 
regarded as permanent 
visitors. 

If you live in or near 
LiverpooI,why not drop 
in and see the club 
for yourself? Meetings 
are held regularly on 
Thursdays at 8 p.m. 
clock time. Don't for- 
get the address: Scout 
H.Q., Church Road, 
Woolton, See you this 
Thursday OM? 



207 



V.F.O.%, Ten-Fifty Transmitter 




<? 



/ 

r 







ALTHOUGH the "Ten-Fifty" Transmitter des- 
cribed last month is a compact and effective 
rig, its usefulness is limited by crystal control. 
Even when several crystals, differing slightly fre- 
quencywise, are available, attempts at operating may 
prove frustrating on a crowded band, and one soon 
realises that if it were possible to QSY slightly a 
clear channel could be found. 

Circuitry 

The complete circuit diagram of the v.f.o. is given 
in Fig. 1. The familiar Clapp configuration as adopted 
for such an oscillator is reliable. Excellent stability 
results due to heavy capacitance "swamping" and to 
the fact that the input and output circuits are very 
effectively divorced from each other. 

The fundamental operating frequency range 
chosen is 3500— 3550kc/s and the L1/VC1 combina- 
tion and associated items tune this range. Coarse 
bandsetting is effected by capacitor CI with trimmer 
TCI providing a means of setting the LF band-edge 
as required to 3500kc/s. Since the effective valve 
oscillator anode is grid 2, the d.c. 
potential to this electrode is voltage 
stabilised at 150V which assists 
frequency stability. 

The fundamental oscillator fre- 
quency plus harmonics appear at 
the valve anode proper where L2, 
tuned to approximately 7000kc/s is 
fitted. All four frequency bands, 
viz., 7, 14, 21 and 28Mc/s are 
workable from the basic v.f.o. 
frequency and "straight-through" 
operation is avoided. To counter- 
act inevitable harmonic "tail-off" 
coil L3 is provided to stimulate 
output on "10". 

Power supplies, viz., 220V d.c. at 
25mA and 6-3V a.c. at 0'6A are 
picked up from the main "Ten- 
Fifty" chassis at the octal socket 
provided, whilst the v.f.o. signal is 
fed via coaxial cable — and only 
3in. is required — to socket Ski 



on the Tx; screened inter-connecting cables are 
essential. 

Constructional 

Dimensions of the metal-work required are given 
in Fig. 2, the simple chassis matching that of the 
main transmitter. In the interests of stability care 
has been taken in positioning components, and the 
layout adopted and recommended is shown in Fig. 3. 
Tuning is accomplished via a vernier reduction drive 
mechanism through an insulated coupler, capacitor 
VC1 being rigidly held by an inverted screening "L" 
section; the band -edge setting capacitor TCI is also 
fitted to the front panel. 

All the coils are easily wound by hand and details 
are given in Table 1. Use of an air -cored coil former 
is preferred for LI whilst L2 must be provided with 
a screening can. Since it is essential for all wiring 
to be taut and rigid 22 s.w.g, copper wire is used 
throughout, adequately sleeved. A single tagstrip 
conveniently anchors power supply leads to the rear 
chassis apron. 




1220V i 

° DC 



Fig. 1: Circuit diagram of the v.f.o. 



208 



BENTLEY ACOUSTIC CORPORATION LTD. 

Suppliers to H.M. Government 38 CHALCOT ROAD, LONDON, N.W.1 Telephone Primrose 9090 

ALL GOODS LISTED BELOW, ACTUALLY IN STOGK, ALL GOODS ARE NEW, BEST DUALITY MANUFACTURE ONLY, AND SUBJECT TO 
MAKERS' FULL GUARANTEE, PLEASE NOTE THAT WE DO NOT SELL ITEMS FROM USED EQUIPMENT NOR MANUFACTURERS' 
SECONDS & REJECTS, WHICH ARE OFTEN DESCRIBED AS "NEW AND TESTED'' BUT HAVE A SHORT AND UNRELIABLE LIFE. 



OA2 
0132 
0Z4 

ia:i 

1.44 
1A5 



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ici 4/e 



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llMi 
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4/e 

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334 


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-JiS~, 



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91>2 

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! 




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42 


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302 
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en 



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1LUEDC 




12/6 


Mill 2/14 a 


\1X4U 


12/6 


S T 37 


23/3 


N'78 


38/4 


N10B 


26/7 


N339 


26/- 


P61 


2/6 


PABOSO 7/6 


£.,...; 


9/9 


PC88 


9/8 


PC95 


6/9 


PCU7 


&/S 


PC900 


21- 


PCC84 


6/- 


PCC8B 


6/9 


PCC88 


10/6 


PCC89 


9/9 


l*i ■< ' t -■: 


8/3 


I'LF-'i 


71- 


PCEF8S 


61- 


PQBS4 


8/- 


PCF8B 


8/- 


I'Ul'Ndl 7/8 


PUF802 9/6 


PGF89S 9/6 


FCF80611/6 


PfiraOS^/B 


l'(;l.3l 


91- 


PCL82 


6/6 


P0LN 


10/3 


i*t;i„s4 


8/3 


PCLS5 


8/3 


PC 1.86 


8/3 


l'<'[,8S 


15/- 


PEN45 


7/- 


PB94EDD 




19/6 


PEN 46 


4/- 


PEN383 9/6 


PEN 3 84 




11/6 


PES453BD 




19/B 


PENA4 19/6 


PEK/DB 


40UO 


17/6 


PFL20013/6 


FL33 


9/- 


FL36 


9/9 


PI, 38 


19/B 


ri,-i 


7/6 


FlJtlA 


7/6 


pijsa 


5/9 


PE83 


6/- 


PL84 


8/3 


PLB03 


12/3 


PI.,-ii)ii 


13/8 


PL604 


16/- 


Pl.MI" 


15/- 


FM94 


9/3 


PX4 


14/- 


PY31 


6/6 


FY32 


10/- 


PV33 


10/- 


PY80 


5/- 


PY81 


5/- 


FY 82 


5/- 


PY83 


5/6 


PV88 


7/3 


PY80O 


6/- 


PY801 


51- 


PH30 


9/6 


QF21 


5/- 


QQVO3/10 




30/- 


QS75/2 


1 




10/6 


QS150/ 


5 




9/6 


BIO 


15/- 


Ell 


19/6 


R12 


6/6 


RIB 


14/11 


E17 


17/6 


SOS 


9/6 


£19 


6/9 



RK34 


7/6 


SP13C 


18/6 


SP42 


12/6 


SP61 


21- 


TDD4 


7/6 


TH4B 


10/- 


TH233 


8/9 


TP22 


61- 


TP25 


5/- 


Tl*262( 


7/6 


TYS-iF 




11/10 


L ABCSO 5/3 


EAF42 


9/6 


UB41 


10/6 


LBC41 


916 


UBG81 


6/6 


UBF80 


5/6 


;}-- 


5/9 


CBE21 


9/- 


CC92 


6/8 


UCC84 


8/- 


FCCS5 


6/6 


LCFSfl 


8/3 


ECH21 


8/- 


I.CH42 10/8 


UCH81 


6/- 


CCLS-2 


11- 


UCE83 


9/6 


UF41 


7/- 


UF42 


9/- 


UF30 


6/9 


UE85 


7/3 


UF86 


9/- 


UF89 


5/6 


EL41 


B/- 


UL4G 


9/6 


UIS4 


6/- 


UMSO 


«/- 


URIC 


8/6 


UU5 


7/- 


UUS 


16/6 


OY1S 


10/3 


UY21 


9/- 


1 Y41 


6/6 


UY85 


6/6 


U10 


9/- 
7/6 


U12/14 


U16 


15/- 


ri7 


61- 


018/20 


(i/8 


U19 


40/- 


U22 


5/9 


DBS 


18/- 


otas 


11/- 


("31 


6/3 


133 


13/6 


U35 


16/6 


E37 34/11 


U45 


15/6 


150 


5/9 


L'52 


4/6 


G76 


4/6 


U78 


3/6 


U107 


17/6 


U191 


12/6 


U251 


12/6 


P281 


8/9 


U282 


12/3 


LT301 


12/6 


U329 


12/6 


C403 


8/6 


U404 


7/8 


CS01 


18/- 


04020 


6/- 


VMP4G 17/- 


VP4 


14/6 


VP4A 


14/6 


YP4B 


11/- 


VP13C 


71- 


VP-23 


2/6 


VP41 


8- 


%'R75 


21/- 


VE103 


5/- 


VE150 


5/- 


YTS1A 


7/- 


VT501 


3/- 


V0111 


B/- 


VG120 


12/- 



V U 120 A 12/- 

vi;i33 71- 

W42 11/- 

W61M 84/6 

W63 10/6 
W76 
W77 
W81M 

W101 26/2 

W107 10/6 



3/6 
2/6 
6/- 



W72!) 

X24 

X41 

Xfll 

X64 

X65 



X101 

X109 

YB3 

Y65 

Z63 

Z77 

Z329 

272S 

Z759 



10/- 
16/6 
10/- 
6/- 
5/6 
5/6 
7/6 
7/9 
BS/1 
29/1 
26/- 
5/- 
5/- 
4/9 
3/3 
11/6 
6/3 
23/- 



Tmn&ittars 
and diodes 
3Q3S8 10/6 



IN 4 '14 
2N2297 
A A* 20 3/- 
AA120 3/- 
AAZ13 3/6 
AC 107 " 
ACH3 
AC114 
AC 126 
AC127 
AC 128 
AC154 
AC155 
AC166 
AC1B7 
AC 165 
Ai • 1 111.1 

AC168 7/6 
ai :nu 8/6 
AC177 5/8 
AC ¥17 3/4 
ACY18 5/3 
ACY19 6/3 
ACY20 4/9 
ACY21 5/9 
ACV22 3/6 
ACY28 4/3 
AU140 8/- 
AIJ149 8/- 
Ai •■'- 1S/- 

AF114 
Al' in 
AKllti 
Al''il7 
AF119 
AE124 

unas 

AF120 
AF 127 3/6 
AP139 11/- 
AF178 10/- 
AF179 13/6 
AF180 9/6 
AF181 14/- 
Af'IBB 20/- 
AFZ12 5/- 
ASY27 8/6 
ASY25 6/6 
A3Y29 10/- 
AV100 26/- 
BA115 2/3 
BAH'-. 9/- 
BA129 2/6 
BA130 2/- 
BCY10 5/- 
BOSJ3 5/- 
BCY33 5/- 



fM 



3/6 
51- 
Sh 
2/- 
3/- 
2/- 
5/- 
6/6 
4/- 
5/- 
5/- 
5/- 



4/- 
3/- 
3/- 
3/4 
3/- 
7/6 
3/6 
71- 



BCY34 


6/- 


I1CY33 


6/- 


BCY39 


5/- 


BCZ11 


3/6 


BC107 


4/- 


BCI08 


3/9 


BC109 


4/8 


11C113 


5/- 


BC115 


3/- 


HC1 IB 


5/- 


BC118 


4/6 


BD119 


9/- 


BFY90 


5/- 


BFY51 


4/6 


BFY52 


51- 


BF154 


51- 


BF159 


51- 


BF163 


4/- 


BF167 


3/8 


BF173 


2/6 


BF180 


12/- 


BF185 


8/- 


BY100 


3/6 


BY101 


11/6 


BY10B 


10/8 


BY114 


6/6 


BY 126 


6/6 


BY234 


4/- 


BY236 


41- 


BY238 


Hh 


BYZ12 


51- 


BYZ13 


51- 


CG12E 


4/- 


UG64H 


4/- 


GD3 


6/6 


GD4 


6/6 


GD5 


6/6 


GD6 


5/8 


GD8 


4/- 


GD9 


41- 


GD10 


41- 


GD11 


41- 


GD12 


41- 


GD14 


10/- 


GDIS 


8/- 


GDIS 


4/- 


G.F.T102 4/B 


GET 1 01 


4/- 


GETlOj 


18/- 


getii: 






15/6 


getii; 


4/- 


OET11517/- 


GETllf 


7/6 


GET119 4/6 


GET57; 


8/6 


GET581 


8/6 


■ . i: l - -.-- 1 0/- 


GET87! 


4/- 


OET87J 






23/Q 


GET882 


10/- 


GET8.S7 


4/6 


GET88S 


4/6 


■■'■..-, j3 4/8 


GET896 4/6 


GET897 


4/6 


GE3113 


3/6 


GEX35 


4/6 


I..RX30 


10/- 


U EX 45 /I 7/- 


GEXB5. 


1 




15/- 


GEXBB 15/ 


UT3 


5/- 


MI 


2/10 


MS 


2/10 


OA5 


1/9 


OA9 


3/6 


OA10 


6/6 


OA47 


*h 


OA7H 


31- 


OA73 


3/- 


OA7S 


1/9 


OA81 


1/9 


OA35 


1/6 


OA86 


4/- 


OA90 


2/6 


OA91 


1/9 



i/9 
2/- 
1/- 
87- 

m 



OA95 
OA182 

OA2(10 
OA-.WJ 

OA2in 
OA-J.I 13/6 
OAK200E3/- 
ua/'.OU 10/8 
OA/,20-.' 9/- 
OAZ203 9/8 
OAZ204 9/- 
OAZ205 91- 
OAZ20B 9/- 
OAK20710/6 
OAZ210 7/- 
OAZ213 71- 
OAZ22413/- 
OCI9 25/- 



txsa 

OC28 

OCT4 
OU25 
0C2I1 
OC2S 
OC20 
OC30 

oi w 

OC36 
OC38 
OC41 
OC42 

oota 

OC44 



5/- 
71- 

14/6 
5/- 
5/- 
6/- 

16/6 
71- 

10/- 
7/6 

11/6 

10/- 
8/9 

13/6 
if- 



0044 PM 8/8 
OC46 1/9 
OC46M 8/- 

OC46 sz- 



ocas 

OCBB 
OC70 
OC71 
OC72 
OC73 
OC74 
OC75 
OC76 
OC77 
OC78 

OOT-D 

OC79 
OC81 

oca id 

OC81M 

OC81Z 

per paii 

OC82 

OC82D 

OOI3 

OC84 

OU123 _ 

OC139 18/- 

OC140 16/- 

OC16B 3/9 

OC170 

OC171 

OC172 

ooooo . 

OC20I 23/- 
OC20S 5/6 
Oi-.'im 5/6 
00204 10/8 
OC205 7/6 
OC20B 10/6 
OCM12 8/- 
OCF71 27/6 
0RF12 15/- 
8X1 /B 3/6 
T82 12/6 
TS3 15/- 
\lil l.-.A 

12/- 
XA102 19/8 
XA103 15/- 
M_4T10(I7/B 
MAT101 8/6 
MAT120 7/9 
MAT121 5/6 
ZE12V7 1/9 



32/6 
85/- 
2/3 
3/- 
8/- 
16/- 
8/- 
2/- 
3/- 
3/4 
3/- 

q. 

ii- 
2/- 
2/- 
Bf- 

5/8 

2'3 
2/6 
11- 
3,/- 
4/B 



2/6 

3/4 
4/- 
5/. 



MATCHED TRANSISTOR SETS 1— OC44 and 2— 0C45 8/8; 1-OCS1D and 2-OC81 7/6; 1 OC82D and 2-OCS2 8/6 {Set of three-OC83 (GET118/119} 8/6; LP15 package {ACU3, AC154, 

AC I, 17. AAI'.'O. 12/6; 1'oHtKge 6d. pCTset. 

B.T.C. I watt Zener diodes. 2-4v:2'7v:3-0v :3-fl»:4-3T: 13v: 16v: 18v:30v. All 3/83. each. 

WE REQUIRE FOR PROMPT CASH SETTLEMENT ALL TYPES OF ABOVE GOODS LOOSE OR BOXED, BUT MUST BE NEW 

ELECTRO LY TICS. Can types: SX 8mfd/500vB/9;8X 16mfd/5O0v7/3; t6mfd/500v 5/6 ; 16 X 16mfd/500v8/9 ;16X 32mfd/450v9/-;3emfd/S00v 7/-j 32 x 32mfd/450«4/9; 50 X 50mtd/ 
350v 5/8 i 60 X 250mfd/275v 9/9; 60 X 250mfd/350v 16/6; 60 X 250 X 10mfd/275Y 13/-; 64 X 100mfd/450v 18/9; 64 X 120mfd/350v 8/6 ; 100 X 200mfd/275v 8/-; 100 X 200mld, l 350v17/9; 
100 X 200 X 60mfd/300v 17/9; 100 X 300 X 100 X 16mfd/275v 22;- 1 100 X 400mfd<'275v 12/9; 100 X 400 X 16mfd/375v 20/9; 150 X 200mld/350v ZO/9 ; 200mfd/350v 10/9 ; 200 X 200 X 
1 0Omf d ;350v 24 /9 ; 10Wmfd/50v 9/9 ;2000mfd/50v 11/9; 5040m Fd/25v 13/6; 5000m Id '50 1 24/9; 8mfd/600u 9/9; 16x 16X 16mld/275» i/6; 50 X 50 X 50mfd/350v 11/-; 16mfd/6O0v 13 -;32nifnf 
450v7/6; *7nifd 450v 7/9; 10,000mfd,30v 26 6d ; Tubular types: 1m<d/500v 3/3; 2mld/500v 2/6; 4mfd/500v 2/9; 8mfd/450v 1/9; 8mfd,'5O0v 3/-; 8x6mfd/450v 2/9; 3X 16mfd/450v 3/-; 
10mfd/50v1/9 ; 16mfd/450v Z/6j 16 X 16mfd/450v 3/6 ; 16x samfd/asOv 3/6; 32mfd,'350v Zj- ; 32mld(450v 3/6; 32x 32mtd/350v 4/9 ; 50mfd/350v S/3 ; 100mfd,'450v 9/6 ; 64mfd/450v t/S. 

EXPRESS POSTAL SERVICE! ALL ORDERS DESPATCHED SAME DAY AS RECEIVED 

Terms oi btutme&t* — Cstsh with ordiar only. PoHtj'PactiiLg fld. per item. Orders river £5 post ittm. No G.O*D. All ordera cleartsU <lay of receipt. Any parct'l insurefi fegMfeo^t dsuua^ein transit 
for 6d. extra, Hours of business, Moil, -Fri. 9.00 to 5.30 p,iu, 9at*^. 9.00 to 1 p s uu Complete iwt ol modern and obsolete valvea r resistors, coudeiisers, transformer^ potenUumuters t miqro- 
phoQes, etc. with term** of business (id. Pleas© note that do tinquiries t-an be answered unless A B.A.E* is enclosed for reply. 



209 



TRANSISTOR 
STEREO 8+8 




A really first-class Hi-Fi Stereo Amplifier Kit. Uses 14 transistors giving 
ft watts push-pull output per channel (Hi W mono). Integrated pre-amp 
with Bass, Treble and Vofranc control. Suitable for me with Oramic or 
Crystal cartridges. Output stage for any speakers irom 3 to IS ohms. 

Compact design, all parts supplied taohjding drilled metal 
[J|^_ work, Cir-Kit board, attractive front panel, knobs, wire, 

s-il'lir, r.uts. biills — no extra.;; to buy. Simple st.ip liv st«p 

instructions enable any constructor to build an amplifier to 

be proud of. 

Brief Specification: Freq. response ±3 ilb 20-20,000 c/a. 
Biif* I most a ■pprox . to + 12 db. Treble cut upprox . to —18 <Jb. 
Negative feedback 18 db over main amp. Power require- 
ments 25 V at O'ti amp. 



STEREO AMPLIFIER 
Incorp" rating 2 F.CLSOs and 1 BZSO, heavy duty, double 
wound mains transformer. Output i watts per channel. 
Full tone and volume controls. Absolutely complete, 

ONLY 

£5.9.6 

K & r. 8/-. 

Super De- 
luxe ver- 
sion with 
EOLiS 
yal vei , 
sep. bags, 
treble and 
balance con- 
trols. Full feedback. 
8 gns. P. & P. 8/-. 




HIGH GAIN 4 TRANSISTOR 
PEDr'TED dECCIT 
AMPLIFIER KIT 

Type TA1 

• Peak out- 
put in erceas 
of li watts. 

• All stan- 
dard British/ 
components. 

• Built on 
printed circuit panel size 6 x 3to. 

• Generous size Driver and Output Transformers. 

• Output transformer tapped for 3 ohm and 15 ohm 
speakers. • Transitory (G1T114 or Bl Mullard OCS1D 
and matched pair of OCS1 o/p). • 9 volt operation. 

• Everything supplied, wire, battery clljia, solder, etc. 

• Comprehensive easy to follow instrurjhuis and circuit 
diagram 8/8 (Free with Kit), Atl parts sold separately. 
SPECIAL PRICE 45/-. P. & P. 3/-, Also ready built and 
tested, 6B/6. P. & P. 3/-, 





FM/AM TUNER HEAD 
Beautifully designed and pre- 
cision engineered by Dormer & 
Wadsworth Ltd, Supplied 
ready Qtted with twin -0009 
tuning condenser for AM con- 
nection, ^realigned FM sec- 
tion covers 86-102 Mela. I.F. 
output 10-7 Mc/s. Complete 
with F.CC85 (61.12) valve and 
fad circuit diagram of tuner head. Another special bulk 
pnrchase enables us to offer these at 27/6 each . P. & P. 3/-. 
Order quickly! 

MATCHED PAIR AM/FM I.F.'s, Comprising 1st I.F. and 
■..'!.'.; l.i- : :t : -i.- . . 1*1 Kc.'.-i/lo-T McK>. Size 1 x IJ x 
2iin.H. Will match above tuner hsad. 11/. pair J &P 2/-. 
60RLER F.M. TUNER HEAD. 88-100 Mc/s 10-7 Mc/a. 
1.1'., 16/- plus 2/0 P, & P. <KCC?5 valves, 8/6 extra.) 
S.T.C. SILICON AVALANCHE HALF-WAVE RECTI- 
FIERS. Type RA8. DOS AF. amps. 900 1M.V. lin. long 
xjin.dift. approx , 1.1st 50,'-. Ut'R PRICE 8/6 Post Fns-. 
SPECIAL OFFER ! PLESSEY TYPE 29 TWIN TUNING- 
SANK. 400 pf+I40 pf. Fitted with trimmers and 5:1 
integral slow motion. Suitable (or nominal 470 Kc/s. I.F. 
Size approx 2xlx llin. OM.Y 8/6, P. & P. 2/6. 
FEW ONLY ! SIEMENS MINIATURE RELAYS. D.F.C.O. 
Cold plated contact*. Size appro*. 11 x | x l^n. 6 V at 
80 mA. ONLY 15/-. P. & F. 1 /6. 

NEON A.C. MAINS INDICATOR. For panel mounting, cut 
ont size Itx I x £in. deep inc. terminal. While case with 
lens giving brighter light. For mains '200/230 v. 2/6 each. 
P. & P. fid, (6 or more pest tree). 

VIBRATORS. Large seJeetiaa of 2. 4, 6, 12, 24 and 32 Volt. 
Non-sync. 8/6; Sync. 10/-. p. & P, 1/6 per vibrator. 
S.A.E, with all enquiries. 




3-VALVE AUDIO 
AMPLIFIER. MODEL HA34 
Designed (or Hi-Fi reproduc- 
tion of records. A.C. Malms 
operation. Ready built on 
plated heavy gauge metal 
chassis, she 7-k" w. x4" d.x 
4^" h. Incorporates i:cr^3 
ELS4, ESJ80 valves. Heavy- 
duty, double wound mains 
transformer and output trans- 
former matched for 3 ohm 
speaker, se p : i rale Bass ; Trilile and volume controls. Nega- 
tive feedback line. Output 4} watt*. Front panel can be 
detached and leads exUmdcd ior remote mounting of 
controls. Complete with knobs, valves, etc., wired and 
tested for onlv £4.5.0. P. A 1'. fi /-. 

HSL"FOUR" AMPLIFIER KIT. Similar in appearance to 
HA34 above hut employs entirely different and advanced 
circuitry. Complete set ol parts, etc. 79/6, P. & P. 6/-. 

10/14 WATT HI-FI 

AMPLIFIER KIT 

A stylishly finished 

monaural amplifier 

with an output of 

14 watts from 2 H 

EI ,843 in push-pull. j| 

Super reproduction j| 

of both music and 1= 

speech, with negli- N 

giblc hum. Separate J- 

inputs for mike and 1== 

gram allow records F— 

and announcements Y 

to follow each other. 

Fully shrouded section wound output transformer to 

match 3-15 Q speaker an d 3 independ ent volume c« m tro Is, 

and separate baas and treble controls are provided giving 

good lift and cut. Vaive line-up 2 ELS4S, F.CC83, EFSB and 

FJKMi rectifier. Simple instruction ijonklot 3/6 (Free with 

part*). All parts sold separately, ONLY £7.9.6. P. & P. 8/6. 

Ats> available ready built and tested complete with std* 

input socket?. 89.5.0. P. & P. 8/6. 




MAINS TRANSFORMER. For translator power supplies. 
Prl. 20 0/240 v. Sec. 9-0-9 at 500 mA. 11/-. P. & P. 2/6. 
i't'i. 2no/240v. See. 12-0-12 at 1 amp. 14/6, P. £ P. 2/6. 
MAINS TRANSFORMER, For transistor power supplies. 
Tapped pri. 200/250T. Sec. 40-0-40 at 1 amp (with elec- 
trostatic screen) and 6*3v, at 'o amp for dial Tamps etc. 
Drop thro' mounting, stack size IJxSJxSlm. £7/6. 
T. & P. 4/6. 

MATCHED PAIR OF Bj WATT TRANSISTOR DRIVER 
AND OUTPUT TRANSFORMERS. Stack size IJxlJx 
Jin. Output trans, tapped for 3 obm and lo ohm output. 
10/- pair plus 2/- P, <r P. 

PARMERO 7-10 watt OUTPUT TRANSFORMERS to 
match pair of ECL82'b in push-pull. Sec. tapped 3-75, 
7-5 and 15 ohm. Stack size 2±xl x2in. approx. ONLY 
12/-, p. * P. 3/., 

7-10 watt OUTPUT TRANSFORMERS to match pair of 
ECLSffs in push-pull to 3 ohm output. ONLY 11/-. 
P & P 2/0 

lft-12 watt OUTPUT TRANSFORMERS. Size 2.Jx2in, 
Clamp fitting. For two I-lLfl4's in push-pull. State 3 or 
15 nhlll impedance. 13/6. T'. J^ P. 2 'II. 



ACOS HIGH IMPEDANCE CRYSTAL STICK MIKES 

Listed at 42/-. Our price 21/-. P. * P. 1/0. 

ACOS CRYSTAL MIKES, High imp. For desk or hand use 

High sensitivity. IS/6. 1". « P. 

1/fi. 

SPECIAL OFFER! MO VINO 

COIL SOKE. Fitted on/off 

switch for remote control 

High finality. Higb or I,ow 

Impedance. (State imp. reqd.) 

BARGAIN PRICE 30/-. 

P. & P. 3/6. 



PRICES 

Amplifier Kit 
Built and Tested 
Power Pack Kit 
Built and Tested 
Cabinet (as illus.) 



£9.10.0 
£T 2.1 0.0 
£.2.10.0 
£3. 0.0 
£2.10.0 



P. & P, 4/S 
P. & P. 4/6 

p. a p. 4/- 

P. &P.4/- 

p. & p. 5/a 



(Special offer— £14,10.0. res I: Free if all above kits 
ordered at same time or pjan be supplied built and 
tested for £18.0.0 Post Free). 

Circuit diagram, construction details and parts list (free 
with kit) 1/6 (S.A.E. 1 




huge purchase: 
e.m.i. 4-speed player 

Heavy 6jin. metal turntable. 
Low flutter performance 200/ 
2c v. shaded motor (00 v, 
tap. Complete with latest 
type lightweight pick-up arm 
and mono cartridge with t/o 
strli for LP.:?*. LIMITED 
NiMKEB OXI.V B3/-. P. & 
P. 6/fl. 



4-SPEED RECORD PLAYER BARGAINS 
Mains models. All brand new in maker's packing. 
E.M.I. MODEL 989 Single Player with unit 

mounted jiiok-up arm and mo:ao cartridge , £5.5.0 

B.S.R. UA25 Changer with n.ono cartridge £6,7.0 

All plus Carriage and Packing 8/8. 
LATEST GARRARD MODELS. All types available 1000. 
SP25 , 30 00, AT60 ete.SendSAE.IoriatestBacgainPrices! 



LATEST B.S.R. X3M MONO COMPATIBLE CARTRIDGE 
With turnover sapphire styli suitable lor playing 78, EP, 
LP and Stereo records with memo equipment. ONLY 23/6 . 
P. <fc P. 1/6. 

SONOTONE 9TAHC .■•omnauMc Stereo Cartridge with 
diamond stylus 50/-. P. & P. 1/0 each. 

QUALITY RECORD PLAYER AMPLIFIER 
A top-quajity record player amplifier employing heavy 
duty double wound mains transformer, 1£CC83, ELH4, 
EZBO valves. Separate Bass, Treble and Volume controls. 
Complete with output transformer matched for 3 ohm 
speaker. Size 7" w. x 3* d. x 6" h , Readv built and tested. 
PRICE 75/-. P. * P. 6/-. 

ALSO AVAILABLE mounted on board with output 
transformer and speaker readv t ( , fit into cabinet below. 
PRICE 97/6. P. & P. 7/6. 

DE LUXE QUALITY PORTABLE R/P CABINET 
Uncut motor board size 141 x 12in. clearance 2in. below, 
oiin. above. Will take above amplifier and any B.S.R. or 
GABRARU autochanger or Single Player unit (except 
AT60 and SP25), Sbie 18xl5x8in, PRICE £8.9.6. 
P. & P. 9/6. 

VYNALR AND REXINE SPEAKER AND CABINET 

FABRICS app. B4in. wide. L'sunllv Lio.'- vd., our price 13/0 
yd. length. P- & P. 2/6 (min. 1 yd,). S.A.E. for samples, 

BRAND NEW S OHM LOUDSPEAKERS 
5tn. 14/-;6Jin, 18/6; «ln. 27/-; 7 x 4m,18/6; 10 x 6in. 27/6. 
E.MJ, Sxoin. with hjgh dux magnet SI/-. E.M.I. 13 J x 
8!n. with high fins ceramic mtgnet 42/- (IB ohm 45/-). 
f. * P. 5ln. •>!-, '■>?.- X .Sin. a.'S, If) K 12in. 3,'li per speaker. 
BRAND NEW. 12in. low. H/E- Speakers, S or 15 ohms. 
Current production by wetl Jaic wn British maker. Offered 
below list price at Sfl/6. P. & P. 5/-. Guitar models: 
25w. '6.6.0; 35w. £8.8.0. 

E.M.L 31ia. HEAVV DUTY TWEETERS. Powerful cora- 
micmaEnct.Availaiii.-in3, 8 or 13 ohms. 15/-, P. & P. 2/6 . 
12in. "KA" TWIN CONE LOUDSPEAKER. 10 watts peak 
output. 8 or 15 ohm. 35/-. F. * P. 3/0, 



35 OHM SPEAKERS 
in, 21/-. P. & P. 2/- per speaker 



HARVERSON SURPLUS CO. LTD. 

170 HIGH ST., MERTON, S.W.19 01-540 3985 

Open all day Saturday Early closing Wednesday, I p.m. 

A ft iv minutes from South Wimbledon Tube Station. (Please write clearly) 



OVERSEAS P. & P, CHARGED EXTRA. 



S.A.E. with atl enquiries 



All items previously ad- 
vertised available. Huge Hi- 
Fi and Component stocks at 
all branches. 



TRADING 



-£ LONDON (MUS 2639) 

10 Tottenham Court Road 
■fc- PORTSMOUTH 'TeL2ZQ34i 

350-352 Fratton Road 
-fc- SOUTHAMPTON 

'Tel. 2S85H 

72 East Street 
if BRIGHTON {Tel. 23975) 

6 Queen's Road 
all mill order Brighton 



• FANTASTICALLY T A D E i, 
popular i m r c y^ 

We offer you lully tenailised polyester/mylar 
and P.V.C. tapes ol Identical quality bj-fl, wide 
range recording characteristics as top grade 
tapes. Quality control manufacture. They 
are truly worth a lew more coppers than 
acetate, sub-standard, jointed or cheap imports, 
TRlf ONE AND PROVE IT YOURSELF. 
Standard Play Long Flay 



3in. 


150ft. 


2/3 


3in. 


226ft. 


3/9 


4in. 


300ft. 


4/6 


4 in. 


450ft. 


b/6 


5in 


600ft, 


7/8 


5in, 


900ft. 


10/6 


5;,'in 


900ft. 


10/6 


5}in, 


1,200ft, 


13/- 


Tin. 


1, 20 Oft, 
Double Play 


12/8 


7tn. 


1,800ft. 
Triple Play 


18/6 


8m. 


300ft. 


*h 


4in. 


900ft. 


13/- 


4in. 


600ft. 


81- 


Sin. 


1,800 ft. 


2W- 


Sin. 


], 200ft. 


lb)~ 


5 J in. 


2,400ft. 


34/- 


• 


1,800ft. 


19/6 


7in. 


9,600ft. 


44/- 


m. 


2,400ft. 


27/- 


Quadrnple Flay 








3 in. 


600ft. 


8/6 



Postngw 1 /- reel. 

Post Free less 5% on tbiee reels. 

Qua n f it y and Trado enquiries Invited. 

NOTE, Zurge tape stocks at till branrtes. 



Please mention 

PRACTICAL 
WIRELESS 

When Replying To 
Advertisements 



210 



Proof of operation is readily found by inserting a 
test meter adjusted to read 0— 50mA in circuit on 
the "hot" side of L2 when at switch-on a reading of 
approximately 15mA should be obtained; V2 should 
also be seen to glow. By disturbing the grid circuit 
of VI in some way — short-circuiting LI momentarily 
for example — should cause the meter pointer to 
swing smartly to a higher reading immediately falling 
back when the temporary short is removed. If, how- 
ever, it is found that the meter indicates a steady 
current of say 35 — 40mA during the test it is clear 
that the circuit is not oscillating and before proceed- 
ing a circuit and component check must be made. 
When the circuit is functioning correctly the external 
meter may be transferred to V2 and when connected 
between pin 7 and chassis should show a reading of 
around 10mA when power is applied. 



Checking 

The station receiver is then switched on and tuned 
to 3500kc/s precisely with the aid of a frequency 
marker. With the v.f.o. dial set to "100" and the 
vanes of VC1 fully engaged, TCI is carefully adjusted 
until the signal is detectable on the receiver; the 
v.f.o. signal should also appear at approximately 
3550kc/s when VCI is tuned to the other end of its 
travel. If excessive frequency coverage results, this 
may be reduced by inserting a fixed value capacitor 
in series with VCI and if it is not possible to tune 
down to 3500kc/s, a small capacitor connected across 
CI may do the trick. To adjust L2 the receiver is 
tuned to 7050kc/s and the v.f.o. signal sought. Using 
the receiver *'S" meter as a guide, the coil of L2 
may be adjusted for maximum deflection. Due to 
the interconnecting cable, coil L3 cannot be adjusted 
until both v.f.o. and transmitter are connected. 

With both units connected the transmitter band- 
switch is set to "10", the key inserted in its jack 
socket and the panel meter switch set to show grid 
current. The transmitter function switch is then 
moved to "Net" and the key depressed whereupon 
the drive control is set to show maximum meter 
deflection. Coil L3 and trimmer TC2 may then be 
carefully adjusted to increase the current indication 
and some 4mA of drive should be obtainable, 
although this is more than normally required. A 
similar amount of drive should also be present when 
the transmitter band-switch is set to the other bands 
covered. 

TABLE 1— COIL DETAILS 



Coif 


Turns 


Wire 


SWG 


Former 
dia. 

(inches) 


Core 


Remarks 


L1 


26 


enamel 


22 


10 


Air 


Close- 


L2 


22 


d.s.c. 


36 


0-25 


Iron 


wound. 

Former 

length— 

1-25in. 

Close- 


L3 


8 


enamel 


30 


25 


Iron 


wound. 

Screened 

Close- 

wound 



p*rSerKf up- 



' ( V "^T ' 1 * '_*»•=» 

■■:\L/ : . : 4L/' ::;;:,:; 3 ' 

T <* T : -v- 1 : 1 

•* — ■!% — *w r. —3-^- -} j P 



""'■'Output : Socket 
dritl to suit 



Bend up 



(a) 



A\- 



3faEiia, 



/Tv* 



5 >2 :. j / 

Baseplate! / 
mounting; / : 3^ 



«". 



.'A. 



m 



downTY 



A- ! j 'A 



Send up | 
} :: : ; :: : ; "V: — M 

t 
Screen B.| 

■ | 

v4 



-3\k- '■ 



:Send up: ; 



sU' 



(b) 



i 



CO 



Fig. 2 (above): Drilling details and dimensions for (a) chassis, 
(b) bracket for VC1, (c) screen B, '(d) screen A. 

Fig. 3 (befow): Layout and wiring of components above and 
below chassis. 



Screened power 
supply leads 



"..:■■ 






Insulated 
coupler 




P^ .Ump 
under 
jr ■ 


f '' i 




To VC1 
TCI 




















— 






— 







CI 



lMC 



Drive 



(a} 



MC = Chassis 



Winding details for the inductors. 



With the v.f.o. complete, the idea of integrating 
the two units should be considered. In the interests 
of t.v.i. elimination a metal case is required; it is 
also essential to fit vertical screens between the v.f.o. 
and Tx units, extended to shield both above and 
below chassis items from each other. 



211 



Two sheets of 16 s.w.g. aluminium each 12 X 8in. 
will provide enough metal for the main case shell 
whilst a further section will serve as a base-plate. 
The base-plate — to which rubber feet are fitted— is 
easily secured to the chassis undersurface flanges 
provided using self -tapping screws. The case and 
panels are grey -lacquered with legends applied using 
transfers. 

After checking the v.f.o. for drift its dial may be 
made more useful if a set of band calibration curves 
are drawn up on graph paper using as a reference 
a Crystal-marker/Receiver combination. It may also 
be additionally interesting to note that the "Ten- 
Fifty" Transmitter may be made a 5-band affair to 
include "80". This may be done by increasing the 
tank coil windings to 32, fitting an additional coil 
to the 6CH6 anode assembly and making SI a two- 
pole, six-way rotary type switch with one of the 
"ways" blanked off. Adequate drive is obtainable 
although a poor or chirpy note may result due to 
'straight through" working. ■ 



Note. A licence is required to operate (he 10-50 trans- 
mitter and v.f.o- Details are obtainable from Radio 
Service Branch, G.P.O. Headquarters Building, St. 
Martins le Grande, London, E.C.I . 



* components li 



Capacitors: 






C1 


150pF s.m. 


C10 


lOOpF s.m. 


C2 


680pF s.m. 


C11 


2000 pF ceramic 


C3 


1 OOpF s.m. 


TC1 


30pF trimmer type 


C4 


1 0OOpF s.m. 




C801 


C5 


lOOpFs.m. 


TC2 


1 5pF ceramic 


C6 


500 Op F ceramic 




trimmer 


C7 


5000pF ceramic 


VC1 


EiOpF variable 


C8 


5000pF ceramic 




(Wavemaster) 


C9 


15pF s.m. 






Resistors: 


Valves : 




R1 


6-8kf2 5W 


V1 


5763 


R2 


6 -8k Q 5W 


V2 


OA2 


R3 


47 kQ 1 W 


Coils: 








See text 


Miscellaneous: 






B9A 


valveholder with skirt and 


can; B7G valveholder; 


panel lamp and lens; insulatec 


coupler; tagstrip; two 


coil formers — 0-25in. 


(one with screening can); coil 


former 1 in. diameter 


; coax 


socket; 2*5mH r.f.c; 


I.O. 


plug; vernier drive 


— Eagle, 


type T502; aluminium 


for case, chassis, etc. 







AUDIO FAIR 1968 —continued from page 1 75 

endless loop tape cassette faculty etc. Models 713, 71 3 H 
and 715 are mono types and models 702, 702H, 722, 
722H, 704 and 724 are stereo models. 

From Philips comes the model PRO 12 recorder 
designed for hi-fi enthusiasts who want something more 
than the ordinary domestic recorder, and professional 
people who want a recorder for studio applications. It is 
a two-speed machine (3 J and 7£ i.p.s.) which can be 
operated either vertically or horizontally and is suitable 
for twin-track mono or twin-track stereo recordings. 
Price is 180gns. Also from Philips comes the stereo 
player N2500. This unit has preanip output which can be 
fed through a hi-fi amplifier to provide full stereo re- 
production. The price was not fixed at the time of going 
to press. 

PICK-UP CARTRIDGES, LOUD- 
SPEAKERS AND TURNTABLES 

There were many new products on show, especially 
in pick-up cartridges, Cosmocord displayed an improved 
version of their Acos Cosmocord; including the Acos 
stylus pack. Latest of the Decca Mark 4 pick-up cart- 
ridges was the FFSS ARC which was being demon- 
strated, and priced at 16 gns. On display by Share was 
the M75E-95G Gard-a-Matic Hi-track cartridge, which 
we understand has been designed specifically for use 
with the Garrard SL95 turntable. Various other new 
models on show by Shure Electronics, including the 
M3JE and M32E, both with bi-radial elliptical stylus. 

Kef Electronics' new addition to their range of 
loudspeaker systems was the Concerto, a three speaker 
system in an enclosure measuring 28 x 17 x 12in. 
Maximum audio input 25 watts r.m.s. 50 watts music 
rating with a frequency response of 30-30,000c/s. 

The Lowther range has been augmented by the 
PM6 MK1, which has an entirely new diaphragm 



assembly, giving an all-round improved performance. 

EMI were offering matched loudspeaker sets, com- 
plete and ready for enclosures. They came in seven 
different sizes ranging from the "250'', with a 5in. 
"woofer" designed for a 0-4 cu.ft. enclosure, up to the 
"950", with a. 19 x I4in. "woofer" for a 4 cu.ft. en- 
closure. The photograph shows the "750" matched 
loudspeaker set, suitable for a 25 cu.ft. enclosure, 
which comprises a bass, mid-range, and two high- 
frequency tweeters. The 750" has a frequency response 
of 20-20,000c/s. 

Amongst the new range from Garrard were the SL75, 
SL65, AP75 and 3500. Models SL95 and SL75 are auto- 
matic transcription turntables, and SL65 a high quality 
automatic turntable. Model AP75 is a moderately- 
priced single record playing unit fitted with a four-pole 
induction motor. Model 3500 is a moderately-priced 
automatic turntable, featuring a low mass pick-up arm 
for use with high compliance pick-up cartridges. 

As an extension to their range of automatic turn- 
tables BSR introduced the UA75. Additional refine- 
ments, exclusive to the UA75 over their earlier models, 
include a heavy cast non -magnetic machined turntable. 
A muting switch provides complete silence during the 
record changing cycle and a "pop" filter suppresses 
switch arcing when the unit shuts off. It also has 
manual facilities and alternative spindles are provided. 

Lustra phone had several new microphones on show. 
In their Series Four, these included the 4-20 multi- 
impedance omni-directional moving coil; 4-30 multi- 
impedance hyper-cardioid moving coil ; 4-50 professional 
multi-impedance dual ribbon studio quality with noise 
cancelling (for the first time). 

Amongst the host of microphones on show AKG 
(Politechnica Ltd.) were showing the D200, a cheap 
version of their earlier model D202, Also appearing for 
the first time was the D224, a microphone for the pro- 
fessional user of the dynamic cardioid type. AKG also 
displayed the K20 and K60 moving coil headphones, 
suitable for stereo listening. ■ 



212 



ff^ roaclurci y 



ELECTRONICS 



GARRARD 4 SPEED DECKS 

Autoohaugers: Model 3400, with cartridge, £9.9.0. 

Mmiel 20DO, with cartridge, £8.8.0. Model 1000, with 

cartridge, (7.7.0. 3P"25 Mk.1T, less cartridge, 

£11.19.6. ATflO Mk.H, lew cartridge. £12.19.0. 

P. 4 P. all changers 7. IB. 

The 'EDB* TEAK FINISH WOODEN PLINTH 

Size 14xl-ii x sjin. Cutout bit Uarrurd 1000, 2000, 

3000, ATB0, BP25. Record Decks (teas cover) 

£3.15.0. P. & P. 6yf>. 

CARTRIDGES: 

CP83 1S/-. ReuterSTD<2 17,'S, RP91.fl 80/-. Mono 

Sonotooe, 2TSS 15/-. Aeos, UPttT 15/-, TC8 less 

bracket 18/0. P. & P. l/-each. 

MICROPHONES: 

Xtal Hand Mikes. 

BM3 and 2001: 35/-. P.SF. 2/6. BUnd lor same 

12/6. P. & P. 2/-. ACOB Mike 45, 81/-. ACOS Mike 

40 18/6. l>yn. Mike DM-301 £2/6. CM21 Xtal 13/6. 

CM'20 Xtal B/6, Magnetic Hm 63C with remote 

control switch 15/-. Tctcphtitm rick-up 10/6. P. A P. 

U-. Xtal Lapel Mike7/6.UulUrMikel2/8.P. &P.1I- 

BARGAINS IN TRANSISTORS: 

AC127. AFU4, 1 la. 116, 117, 113, 119. OC169, 170, 

171, 172, 300, 202, 803, 204. AC120, AUY40, ACY17, 

AF212. BCY10. 12, 33, 34, 38, 39, B1''Y60. 51, 52, 

00. 6/S each. P. & P. fld. OA202 1/3. P. « P. 8d. 

OAZ206, 20S, 6/6. P. & T. 6d. OC72, 75, 82, 83, 

AAZ12, BYS*. BCZil. 3/6. OC71, f»I, 3/-. R.F. 

Packs 1 OC44, 2 OC45 8/6. A.F. Packs 1 OCS1D, 2 

OC81 (Mallard), 8/6. GET 113. 15 ed Spot £/-. QC28, 

2rt, 29 9/6. ORP12 Light Ct II 8/6, Diodes OAB1 3/3. 

(JA91, OA95 1/9. P. & P. 1/-. 

TRANSISTOR ELECTROLYTICS: 

1. 2, 4, 5, S, 10 , 16, 25 , 32. 50 , 1 00 mid IB volt working 

1/3. P. & P, 1/-, 

250 mfd DC 3/-. 500 mfd 12 v DC 3/-. 500 mid 25 v 

DC 3/6. P. <£ P. 1/-. 

RESISTORS. } watt 10% from 4-7 ohm to 10 meg 51, 

each, 4,'- doz. P. A P, 1/- (minimum ordrr 8/8). 

PAPER CONDENSERS for Cross- Over Units 2 mid 

E 6. P. A P. 1/-. 

FEBE03 RODS. 6' X t',2/-;6* X '/,«*, 8/6; 41* X 2*. 

3/-; 6" x (*, 3/6; B' x V. 3/-. P. 4 P. 1/- each. 

FERROX RODS WITH COILS. 4r*f", 3/8; 

8" x B .l u \ 5/6. F. A P. I ,'- each. 

PIA50 KEY PUSH BUTTON SWITCHES. 7 button, 

inc. mains on oG. 8 banks of 6 P.C.O. B/6. P, A P. 1/.. 




SPEAKER SYSTEMS 

THE C ASTON COLUMN 
This is a column, cabinet. 
Size 224 x 5 x 6 } in,, Dtted 
with 3 speakers. This will 
handle S watts and will 
improve the quality of 
any tape recorder, or 
record player, Finished 
in wood grain cloth and 
sandstone Yynalr, A real E 
bargain at 59/6p1u.i 10 ;!•:■;■ 
P. A P. 

THE MILTON. A Hi-Fi Bookcase Cabinet. Size 
9 x 5 X Sin. with 5in. speaker. Finished In Teak 
doth with hold silk front. 80/-. P. A P. 3/6. 




THE STEREO. A sup- 
erior extension cabinet 
fitted wit h two 7 X 4 in. 
speakers. Size 16x9x 
Sfln. Finished in fawn 
Vyna ir w it h n atura 1 1 eak 
ends. £8. P. & P. 5?-. 




THE IMP, Extension Speaker Cabinet. 
WedgeshiiF'-'d, size 7 t x Jin. ntted with 
7 x 4in, speaker. Covered with attractive 
walnut with fawn Vvnair front. Key- 
hole slot in back. Only 85/6. Post 2/6. 
Note: All cabinets new and made with 
|in, chipboard. All speakers ei TV 
reconditioned hi mix magnet. AH 
carefully tested before despatch. 



HAYD0N SPEAKER SYSTEM. Size 16* x 15 x 71in., 
Speaker and volume control. Fabric covered. £4.17.6. 



SPEAKER ENCLOSURES 

Tod* Corner Cabinet 20 x 10 x Tin. takes 10 x 6In 

speaker covered in Rexinc and Vynair, 45/-. P. A P, 

7/6. 

Hajdon, 16J x 15 x74in. fabric covered suitable for 

12in. speaker, 45/-. P. 4 P. 8/-. 

Table top or wall mounting enclosure for 13| x Sin. 

speakers 37/6. P. A P. 6/-. 

Corner Cabinet to natural teak finish foT 131 x Sin. 

speaker also cut out for tweeter, £3,15,0. P. A P. 8/6. 

Hi-Fi Bookshelf sneaker enclosure foam lined, 

cabinet size 10jx51x7Jin. Teak finish, £3.0.0. 

P. ft P. 6;-. 

Wooler for above £3.0.0. P. A P. 2;6. Tweeter 12/6. 

P. A 1'. 1/8. Condenser for crossover 3,'S. Terminals 

3/6 pair. P. A P. 1/-. 

SPEAKERS: 

EIsk! Heavy duty Ceramic Magnets 11 ,000 line. 10in. 

round 10 x 6in. 3 ohm or 16 ohm, 4.S/6. P. A P. 3/6. 

8io. roond 15 or 3 ohm, 42/8. P. * P. 3/6. E M.1. 

13| x Sin, 15 or 3 ohm, 43/6. F. A P. 3/6. E.M.I. 

Tweeter, 15/-. P. A P. 1/6, Bakers 12iu. 20 watt 15 

ohm, £5,5.0. 1*. A P, 3/6. 8 X otn. Elliptical 30 ohm 

30/-. P. ft P. 3/6. 5»n. round 30 ohm 17/6. P. ft P. 

216. 5 x3m. 15 uhm 17/6, P. A P. 2/6, 7x4in. 

35 ohm, 22/6. P. A P. 2/6. All other speakers supplied 

— Goodmans, Bakers, W.B., Wharfedafc, Eagle, 

Triple tone. 



PYE TV REMOTE CONTROL UNITS. Grey and 

Red plastic case, 2 white/silver knobs, 2 volume 

controls, 500K and 16 OK, small chassis. 7 yards 

5 -way cable with octal plug. Brand new, boxed. 

Only 5/6. P. A P. 1/9. 

EARPIECES WITH CORD AND 3,5 mm. plug. 8 ohm 

magnetic, 3/-. 250 ohm 4/-. 180 ohm with clip. 6/6. 

Xlal H-.r. & P. 6d. 

TRANSISTOR SPEAKERS I ohm 2in. 8/6; 3ln. 10/6: 

3i in. 12/6, P. ft P. 1/-. 

VYNAIR. Widths from 4!) to 54in. 13/6 vd, of! roll. 

P. ft P. 1/9; i yd., 7/6. P. A P, 1/9, Send Od. stamps 

for samples, 

SPEAKER MATCHING TRANSFORMERS, 3, 7, 15 

ohms, 8 watts 11/8. P. A P. 1/6. 

PANEL LIGHTS. 6v Red, Blue, Green, Yellow, 

White (uses Lilliput bulbs) 3/- each. P. A P. 1/-. 

NEONPANELLIGHTS2f)0-250v3/-each.P.AP,I/-. 

ROTARY SWITCHES: 2 pole Mains Switch 3/-. Ipole 

12 wst, 2 pole 2 wav, 3 pole 3 way, 3 pole 4 way, 4 

pole 3~way, 3/6 each. P. ft P. 1/-, 



Stockists of • Ragle Products • 
Goodmans • W.B. • Wharfedale. 
• Bakers V Trip let one • linear. 
All makes of amplifiers and speakers 
supplied. 3.A.E. please. Trade 
terms to bona fide dealers. 



92 MITCH AM ROAD, TOOTING BROADWAY, 
LONDON, S.W.17 Telephone 01 - 672 3984 

(four minutes from Tooting Broadway Tube Station) 
(Closed all day Wednesday) Note: Shop closed June 1 7th-29tf» 




BASIC 




ELECTRICITY (5 vols.) 
ELECTRONICS (6 vols.) 



You'll find it easy to learn with this out- 
standingly successful NEW PICTORIAL 
METHOD — the essential facts are explained 
in the simplest language, one at a time, and 
each is illustrated by an accurate, cartoon- 
type drawing. The books are based on the 
latest research into simplified learning tech- 



niques. This has proved that the PIC- 
TORIAL APPROACH to learning is the 
quickest and soundest way of gaining 
mastery over these subjects. 

To TRY IT, IS TO PROVE IT. 



The series will be of 

exceptional value in 

training mechanics and 

technicians in Electricity, 

Radio and Electronics. 

WHAT READERS SAY 

" The books are the best 1 have ever seen on this subject, /t did not 
take me long Jo decide they were Jim! ifhol / had been looking for.' 1 

G.E.C., Belfast. 
"These are remarkably sound books— and should speed up the 
acquisition of a quite ezk t» $t 94 "Basic." knowledge.'* 

P.W.S., Chrlsteburch, 
"Tndy a mindful of information," R.J., Antrim, 

" The Manuals are mil of this world for simplicity In learning about 
Electronics." P.J.. Durham. 

"Hay 1 state hotc delighted t am teilh I he books, and what a eontrast 
1 o the many text books I have attempted to struggle through." 

G.J., Hull. 
A TECH-PRESS PUBLICATION. 



POST NOW FOR THIS OFFER ! 



To the SELKAY BOOK CO.. 60 HAYES HILL. BROMLEY. BBS THP 

Please send me WITHOUT OBLIGATION TO PURCHASE, one of the shore sets on 7 DAYS FREE TRIAL. 
I will cither return set, carriage paid, In good condition within 7 days or send the following amounts. BAB10 
ELECTRICITY 72/-. Cash Price or Down Payment of 15/- followed by 4 fortnightlv payment* ol 15/- each. 
BASIC ELECTRONICS 84/-. Cash Price or Down raymeni of 15/- followed by 6 fortnightly payments ol 
15/- each. This offer applies to UNITED KINGDOM ONLY. Overseas customers cash with order, prices as 
above. 

Tick set required (Only ONE set allowed on free trial). 

BASIC ELECTRICITY □ BASIC ELECTRONICS |J 

Price* include Postage and Packing. 

Signature 

( if under "it signature of parent or yttardiatl) 

NAME 

BLOCK LETTERS 

J-'C LI, POSTAL 

ADDRESS 



213 



Widely acclaimed at the*l96 

AUDIO FA\m 




ACOUSTICALLY 
CONTOURED 

60-16,000 Hz 

15£1 IMPEDANCE 

LOADING UP TO 
14 WATTS 

BRILLIANT 

TRANSIENT 

RESPONSE 

NEW MATERIALS 

NEW STYLING 

ALL BRITISH 



a brilliant advance in 
high fidelity loudspeaker design 



When the Sinclair Q.I 4 was demonstrated at this year's 
Audio Fair, it delighted some of the world's keenest and 
most critical listeners. It more than held its own against 
far more expensive loudspeakers and proved beyond all 
question that research and careful design could produce 
a Quality loudspeaker for a remarkably low price. The 
Q.14 measures 9|in. square on its face and is finished in 
black matt with natural aluminium bar embellishment. 
Its unique shape allows it to be tried and used in a far 
wider choice of positions than conventionally shaped 
speakers. A pair in stereo give true "in-depth" perform- 
ance with complete freedom from listening fatigue. If 
you missed the Audio Fair, why not hear this speaker in 
your own home. Should you not be pleased with it, your 
money including cost of return post to this office will 
be refunded in full. 



ACCLAIMED BY 
USERS TOO! 

P.G. of Newry, N, Ireland writes: 
"I have always been cynical 
about letters written to manu- 
facturers p-aising their goods, 
but I am so delighted with the 
(two) Q.14 speakers that [ feel 
I must write this for it sounds 
that you heve given me a new 
collection of records. I con- 
gratulate you on a marvellous 
speaker at V'jry reason a bie cost. " 




SUPERB VALUE AT £7- 19- 6. 



, __> 

SINCLAIR RADIONICS LTD, 22 Newmarket Road. 
Cambridge Phone CICA-352996 



214 




COMBINED 12 WATT HI-FI AMP AND PRE-AMP 



The small amplifier 

with the enormous output 

No constructor's amplifier has ever achieved such success as the 
Sinclair Z.12. It has fantastic power-to-size ratio, and far greater 
adaptability. It will operate from batteries or PZ.4 mains power supply 
unit, and gives superb stereo reproduction for modest outlay. 
Thousands are in use throughout the world — in hi-fi, electronic 
music instruments, P. A., intercom systems etc. This true 12 watt 
amplifier is supplied ready built, tested and guaranteed together with 
the Z.l 2 manual which details control circuits enabling you to match 
the Z.12 to your precise requirements. For complete listening satis- 
faction use your Z.12 system with Q.14 loudspeakers. It assures 
superb quality with substantial saving in outiay. 

* IDEAL FOR BATTERY OPERATION 

3 x 15 x 1 Jin. • Class B Ultralinear output • 15- 
50,000 Hz ± 1dB # Suitable for 3. 5. 8 or 15D 
speakers. Two 3-ohm speakers may be used in 
parallel • Input — 2mV into 2fcfi • Output — 12 
watts R.M.S. continuous sine wave (24w peak) 15 
watts music power (30w peak) • Ready built, 
tested and guaranted 

SINCLAIR PZ.4 STABILISED 
POWER SUPPLY UNIT 

A heavy duty A.C. mains power supply 
unit delivering 18V D.C. at 1-5A. 
Designed specially for Z.1 2 
assemblies. Ready built and 
tested. 



89/6 




99/6 



THE SINCLAIR STEREO 25 PRE- AMP/CONTROL UNIT 

For use with two Z.12's in stereo. With pull control and 
matching facilities. Attractive aluminium 



front panel and knobs. 

THE SINCLAIR GUARANTEE 

Should you not be completely satisfied 
with your purchase when you receive 
it from us, your money will be refunded 
in full at once and without question. 
FU LL SERVI CE FACI LITIES AVAI L- 
ABLE TO ALL PURCHASERS. 



£9. 19. 6. 




49/6 

Ready built with 
magnetic earpiece 

59/6 

Mallory Mercury Cell 
RM.S75 (S needed) ea. 2/9 



l 4 / 5 x !»/,. x V. 



BUY IT 

IN KIT FORM 

OR READY 
BUILT 



This amazinglytiny receiver 
is the ultimate in personal 
istening. The Micro matic as easy to 
have with you as is your wristwatch. 
It has enormous power and range, and 
the magnetic earpiece now supplied 
assures marvellous quality. Hear how 
Radiol and other stations simply pour 
in over the whole medium waveband. 
Build it yourself or buy your Micro- 
matic ready built. This is the set you 
will never be without once you hear it 
for yourself. 



To: SINCLAIR RADIONICS LTD., 12 NEWMARKET ROAD, CAMBRIDGE ■ — — ' 

Please send post free items detailed below: 



For which I enclose cash! cheque I money order 



NAME. 



ADDRESS 




PW.7 



215 



(ForAF117) 5/4 

(ForAF117) 5/7 

(ForAF117) 5/7 

(ForAF117) 6/- 



WEYRAD 

COILS & TRANSFORMERS FOR CONSTRUCTORS 

Special versions of our P50 Series are now available for AF1 1 7 or OC45 Transistors. They can be used in the standard 
superhet circuit with slight changes in component values, details of which are given in the lates: edition of the 
Constructors' Booklet priced at 2/-. "*" 

Oscillator Coil P50/1AC (For OC45) P50/1AC 

1st I.F. Transformer . P50/2CC (For OC45) P51/1 

2nd I.F. Transformer P50/2CC (For OC45) P51/2 

3rd I.F. Transformer „ P50/3CC (For OC45) P50/3V 

Rod Aerial RA2W 1 2/6 

Driver Transformer LFDT4/1 9/6 

Output Transformer OPT1 10/6 

Printed Circuit PCA1 9/6 

I.F. TRANSFORMERS & COILS FOR VALVE CIRCUITS 

Production of Tuning Coils (Type "H") and I.F. Transformers is being continued and details of these and our 
other components are given in an illustrated folder which will be forwarded on request with 4d. postage please. 

WEYRAD (ELECTRONICS) LIMITED 

SCHOOL STREET, WEYMOUTH, DORSET 



PADGETTS RADIO STORE 

OLD TOWN HALL, LIVERSEDGE, YORKS. Telephone: Cleckheaton 2866 



Xew Boxed TV Tube. Type MW43/69. Top grade not a second. 

12 months guarantee 47/-. Carriage 10/-. 

Stew TV Tubas with slight glass fault all types 19 and 17in. 50/-. 

Carriage 10/-. Twelve months guarantee. 

Reclaimed TV Tubes with six months guarantee 17in types AW43/ 

88, AW43/80. 40/-. MW43/69, 30/-. 14in types 17/-. All tubes 10/- earr. 

Good TV Tubes tested perfect but no guarantee. Type AW43'80 and 

MW43/69. 17/- each plus carriage 10/-. 

Speakers Removed from TV sets all perfect 3 ohms P.M. Sin. 

round 8/6. P. & P. 3/6. 6in. round 3/- P. & P. 3/6. 7x4 5/-. P. & P. 3/6. 

Six for 34/- post paid. 5in. round 3/-. P. & P. 2/9. 6x4 3/-. P. & P. 2/9. 

Six for 23/- post paid. Slot speakers 8 x 2i 5/-. P. & P. 3/-. Six for 30/- 

post paid. 

Hew ISiii, Speakers with Built-in Tweeter, 3 or 15 ohm. 2876. Post 

paid. 

Special Sale of ex W.D. Gear. R.A.F". tube unit type 266 just like 

the 62A unit. Fitted with VCR97 tube mu-metal screen lull of E.F. 

valves complete with outer case. Grade 1 27/-. Grade II 22/-. Both 

units 10/- carriage each. 

Tube Unit type 7931. Complete with tube type 2292. Front marked 

in figures. Many spares less four BF91 valves 10/- carriage 10/-. 

88 sets complete with Valves, Phones and Mike less Send Receiver 

Switch, 20/- Plus P, & P. 10/-. 

Breaking up type 19 sets. Meters 6/6. P. & P. 3/-. Metal toggle 

switch Oil. P. & P. 6d. 7/6 doz. P & P. free. Jack socket ;Bd. P. &P. 7d, 

12/- doz. P. & P. free. Pointer knobs 6d. P, & P. 6d. 7/6 doz. P. &P, 

free. Relay 100 ohms 1/9. P, & P. 1/6. 24/- doz P.&P. free. 19 sets 

less meter. Relays, Valves and Toggle Switches for spares, 10/-. 

carriage 10/-. 

19 Sets bench tested as a Receiver these sets will not transmit. 

Power Pack Required less 607. 35/- complete with valves. Carriage 

10/-. 

1355 Set complete with 5U4, 6x5, Six SP61 valves. New condition 

good break up line. 10/-. Carriage 10/-. 

Snort wave TX Chassis. Two valve battery model, 8/6. P.&P. paid. 

Model Makers Motor 36 volt will run from 12 or 6 volt. 7/6. P. & P. 

paid. 

Motors removed from Washing Machines J h.p. 1400 revs 250-200 

volt A/C complete with pulley, 26/-. P. & P. 10/-. 



VCR97 tube complete with mu-metal screen 10/-. P. & P- 5/-. 

Top Grade Mylar Tapes. 7" standard 11/6. 7* Long Play 14/-. 

7" Double Play 19/8. 5" Standard 7/9. 5" Long Play 10/-. Plus post on 

any tape 1/6. 

Jap Ear Piece small or large plug 1/11. Post paid . 

Silicon Rectifier 500 M.A. 800 P.I.V. No duds 2/6. Post paid. 24/- 

doz. P. & P. paid. 

G.P. Diodes all perfect. Guaranteed. 3/6 doz. P. &. , paid. 

I'ntested Semi Slim Masteradlo T.V. Sets. Fitted with AW43/ 

8B tube complete fair cabinet E4. Carriage 15,- 

VALVE un 
Ex Equipment, 3 months' guarantee 
Single valves post 7d. over 3 valves p. & p. paid. 

lOFl, EF80, BB91. ECL£0, EF50, PY82, PZ30 . 20P3. Ail at 10/- per doz. 
Post paid. 



ABP12 


1/6 


EB91 


9d. 


EFP80 


3/- 


ECC81 


3/- 


ECC82 


3/- 


ECC33 


4/- 


ECL8Q 


1/fl 


EF50 


1/- 


EF80 


1/8 


EF91 


cm. 


EL36 


ft/- 


EY51 


2/6 


EYB6 


5/- 


KT36 


5/- 



PCC84 


21- 


PCF80 


21- 


FCL82 


4/- 


PCL83 


5/- 


PL36 


5/- 


FL81 


4/- 


FY33 


5/- 


PY81 


1/6 


PY82 


1/6 


PZ30 


5/- 


U25 


5/- 


U191 


51- 


U281 


51- 



U282 


5/- 


VJ301 
U329 


5/- 

5/- 


U251 


5/- 


U801 
5U4G 


8/6 

4/- 


6B8 
6BW7 


1/8 
2/6 


6K7 
6K25 


1/9 
5/- 


6P25 
6U4 
6V6 


5/- 

5/- 
1/9 



6P28 

10C2 

10F13 

185BT 

20D1 

20L1 

20P1 

20P3 

30PL1 

aapis 

30F5 

30FL1 

6/30L2 



5/- 
5/- 
2/6 
8/6 
3/- 
57- 
5/- 
2/6 
5/- 
5/- 
2/6 
51- 
51- 



EF50, 10/- doz. Post paid. 

New valves ex units, 807. 5/6; 6K7, 2/-: 6K3 2/6: 6X5. 3/-; 6SN7, 3/-: 
GV69T, 3/6; DF61, 2/-; DL92 2/-; DK91, 21-; 3Q4, 3/-: A1B20, 1/6! 
B13H6 21-. CV valves all at 2/- each. CV131, CV136, CV138. CV137. 
CV261, CV4025, CV4063, CV14CJ, CV3998 CV858. 

Untest TV Sets complete 12 channel. 17 ins. 50/-, carriage 15'-. 
14ms. sets 30/- carnage 15/-. 12ins. sets 20/-, carriage 15/-. 
Cbassiswith spares including 3m in iature relays 10/-, plus P, & P . 6/-. 



216 



PRINTED CIRCUIT KIT 

BUILD 40 INTERESTING PROJECTS on a PRINTED OTfiCtUT CHASSIS with 
FARTS and TRANSISTORS iram your SPARES BOX 

CONTEXTS; (1) 2 Cupper Laminate Boards 4V" x 24"- (2) 1 Board for Matchbox 
Radio. (3) 1 Board for WrUtwatch Radio, etc. (4) Resist. (0) Resist Solvent, iii! 
Etohant. (7) Clcnint-r.' hetrreascr. (8) |ii-page Booklet Printed Circuits for Amateur*. 
(9i 2 Miniature Kailin I'iais SWilTWiLW. Alao tree with each kit. (10) Essential 
Design Data, Circuit*. Chassis Plans etc. for 4(1 TRANSISTORISED PROJECTS. 
A very comprehensive selection of circuits to suit everyone's rn inurements. Many 
recently developed very efficient designs published for the first time, including 
10 new circuits. 

EXPERIMENTER'S 
PRINTED CIRCUIT KIT 

8/6 

Postage & Pack. 1/8 (UK) 

Commonweal th : 

8LRPACE MAIL 2/- 

AIR MA1T, 8/- 

Anstpiiiia, New Zealand, 
South Africa, Canada, 

(1) Crystal 3et with biased Detectnr. (2) Crystal Set with voltage-quailruplcr 
detector. (3) Ciyatal Set with Dynamic Loudspeaker. (4> Crystal Tuner with Aodto 
Amplifier. 15> Carrier Power Graven-inn Heceiver, (d> Split -Load Neutralised Double 
Itetlfx, 17) Matchbox or Photocell Radio. (Si "TIUFI.EXQV Triple Refles with self- 
adjusting regenerating (PatenL Pending). (9) Solar Battery loudspeaker Radio. The 
smallest 3 designs vet offered to the Home Constructor anywhere in the "World, 3 
S'.iliiiiirii.irn-r ftadiii Iti-eeivers l:a»i-il r-n the "TriHexon" circuit. Let ua know if you 
know ol a smaller .le-dim puiilishcil anywhere. (10) Postage Stamp Radio. 3Uc only 
1-63' x -B5" K -aii". (11) Wristwatch Radio I-IJT x -80' x -SS". (12) Ems Kadi" 
■70* X -70* x -So*. (13) Bacteria-powered Radio. Runs on sogar or bread. (14) Radio 
Control Tone Receiver. (IS) Tran«lstor PIP Amplifier. (16) Intercom, (17) 1- valve 
Amplifier, (IS) Beflabta Burglar Alarm, (IB) l.ight-UeekinK Animal, Guided Missile. 
(id) Perpetual Motion Machine. CJli Metal Lii:1.i-i-t,iir. (ii) TraiiHixt'jr Tkh ■.■>$) 
Human Body Radiation Detector. ('24) Man/Woman Discriminator. (25) Signal 
Injector. (26) Pocket Transceiver I Licence required), (27) Constant Volume Intercom. 
(•28) Remote Com rol of Models by Induction. (29) Inductive -Loop Transmitter. (30) 
Pocket Triple Bedex Radio. (3D Wristwatch Transmitter/Wire-less Microphone. (32> 
Wire-less Door Bell. (33) Ultrasonic Switch/Alarm. (34) Stereo Preamplifier. (35) 
Quality Stereo Push-Pull Ainplilli-r. (36) Liiht-Beam Telephone "Fhotoptume". (37) 
Light-Beam Transirillter. (3 s ) Silent TV' Sound Adaptor. (39) Ultrasonic Trans- 
mitter. (40) Thyristor Drill Speed Controller. 

YORK ELECTRICS 

333 YORK ROAD, LONDON, S.W.11 

Send a S.A.B. for full detail*, a brief description and Photographs of alt Kits 




• CA3020 (LINEAR I. C.\ WIDE-BAND 

\la 12- Lead TO -a Case/ 

AMPLIFIER 

COMPLETE WITH DATA SHEET 33 - EACH 

ALUMmlUM DIECAST BOXES -Appros, dimensions; Type A 4» i 3J i Iln. 
deep at 7,6 each. Type B4; i ::, x >Ui. deep at 10;- each. 

STJBMTNIATT/RE TAGBOARDS— (IJin. wide), 8-way at 1/3. IS-way at 3/- each. 

COAS, SOCKET— Surface mounting, Sy\oa. Insulated, 1/8 each. 

COAX. PLUG— Belling Lee Type 1,734, 1/4 each. 

RESISTORS — CARBOH FILM— ) watt, 5% 10 ohm to 10 Megohm, 8id each or 

3/3 doz. 

CARBON PRESET POTENTIOMETERS —Vertical or Horizontal mounting. 

200 ohm to 2 Megohm, (Steimlapl values) at 1/4 each. 

MIHIATURE CARBON POTENTIOMETERS— lln. dia. x [in. deep; |fa ,li.<i. 

spindle. 5 Kohm to 2 Megohm LOO. and A Ktihm tu 1 Megohm. LIS. at 3/- each 

or 2/9 each (or 4 or more of the same value. (Standard values only). 

CAPACITORS— CERAMIC TUBULAR— (Standard Values) 4-7pF— ' 0-OTjiP 

Sd each, 

CAPACITORS— SILVER MICA— 5pl'— SOOpF 1/- each [Standard Values), 

CAPACITORS — TAKTALUM BEAD — A range ol 36 miniature units, with 

values from 10ou,F/3vir to O-lpLlVUflvw alt values at 4/3 each. 

BEEHIVE TRIMMERS— (3— »0pl-) at B/8 each. 

DIODES — OA70. OA79, OA81. OA8S, OAB1, 0A200, OA202 at 2/- each, 

TRANSISTORS -OC44.5/B: 0(,'4(i, 5/4; QC71.3'B;OC72, B/4; OC83,4/-:OC170, 

7/8;"BrjlU7. 3/11; RO108, 3/3: BC109, 3/11; i!('15I_. 5/9; Oi:siz. 10/-; \C\-iV6. 



8- 2N371I, 4/3; 2X3S'19(I-'KT>. 14/3; as:i^o(FET), 20/-: 2A ! 26-i«iti:jT), 
10/B; BRY39(SCS), 10/6; A WIDE BAN OR OF OTHER TYPES ARK IN 
STOCK, INCLCOINC asanatl SERIES— All groups at 3/3 each (or, 8/6 
each In multiples of 5). 

Due to heavy demand 2N3819 FET and 2N3S20(FET) are subject to a delay ol 
np to three weeks, if current stocks run.- out. 
Postage and packing is charged at 1/- in the JJ (Minimum ol 2/- per order). 

M. R. CLIFFORD t COMPANY (COMPONENTS DEPT.}, 
209A, MONUMENT ROAD, EDGBASTON, BIRMINGHAM, 16. 

Term-: C.W.O. (or C.O.D.— over £3 only) Tel.: 021-454-6510 

Please cr0s» all cheque* and P.O.*s 



Well worth reading through 

GUARANTEED BRAND NEW GOODS OF FINEST QUALITY AT THE 
LOWEST PRICES YET: IMMEDIATE DISPATCH 

RECORDING TAPE: FINEST PROFESSIONAL QUALITY MYLAR. 
BRITISH PRODUCTION, STANDARD PLAY: 5in. 600ft.. 7/3;5j.in., 850ft,, 
8/9; 7 in. 1200ft.. 11/3. LONG PLAY: Sin. 900ft., 10/-; 51 in, 1200ft,, 11/3; Tin, 
1800ft., 18/-; 3 in- 225ft. Message, 3/6. (Postage and packing 1/- per reel: 3 or 
more reels post paid.) _ . _ 

MICROPHONICS: CRYSTAL: Acos 40. Desk, 15/6 1 3': Acos 4o Curved 
handgrip. 17/3 (1(6), Acos 60 Stick, 20;3 (1/6). Acos 39 stick. 26/6 (1/6). Rec- 
tangular cream plastic hand, ideal tape recorder use, 7/6 (1/6). LAPEL. 
8/6 (!/-)■ DYNAMIC: MSlo, 50Kn, 3iin. x tin., instantly removable from a 
floor stand, with adaptor to fit on base provided, lavalier included, 37/6 
(2<6) MSll. similar, but fixed on flexible swan neck to switch-fitted base, 
427- (2/6). ALL with leads. SPEAKERS: British made, high quality 12in. 
Hound, fitted tweeter. 6 watts, 3 B or 15 n , 33/6 (3 6) : Tin. x 4in. Elliptical 30 
for TV. Car. domestic sets. 15/- (2 6). 2iin. 80n (Fane). 4/- (1-). 21in. 30 
(Emp.). 6 6 (l-'-i. EARPIECES: with lead and min. plug. Mauv;eti c 1 6: 
Crvstal 2''fl (either, 6d.). PICK-IP CARTRIIKiKS: All stylii fitted, 
sUndard replacement actings: Mono GP.'67-2 12;6; GT1Z-2 Stereo 20;-; 
GP93 newest stereo 22/-: GP91 mono do luxe 16/-; GP/91SC Stereo Com- 
patible (both mono and stereo) 18/6: GP7MSS Stereo Compatible. CEHAMIC 
top quality for expensive outfits 38/6 (1/- on all types). REAL DIAMOND 
8TY11I: TC8LP. TC8 Stereo. TCSLPiStereo. Studio O LP Ronette, BF40 
LP Ronette. GC2. GC8, GP65/67 all at 6/11 each, and GPS1/LP 12, 6 (Post all 
tvpes 6d.l. SAPPHIRE STYLD all above types available 2'11 eacb (6d.). 
INTERf:OM/ltAB¥ ALARM: 2-statton. PP3 battery operated, with buzzer 
for remote call when switched off. instructions. 50ft. cable, plugs, battery 
complete 52/6 (3,-). Fitted easily by anyone in minutes. PF3 type 
ItATTEIUES: new guaranteed stock l.'-each. AMPLIFIER : aw, 4 transis- 
tor 23 in. x 2Hb- x lHn.. 9v bate, operated. 15. 8 or3a output, very efficient 
45. 6(1'6). Battery not supplied. TAPE RECORDER : Latest portable, batt. 
operated RA65: Blio. x 7 x 21 in., fixed handle, 3in. reels. 2 track complete 
with reels, tape, mike. batt. and earpiece for optional private listening, 
still only £5.5.0 <4'6>- 

l*P« BATTERY ELIMINATOR: (A.C.) 17/6 (2/6). PRINTED CIRCUIT 
PANELS— eight assorted boards with transistors, (Guaranteed minimum 
30) also diode*, resistors, capacitors, etc.. 8- (2'->. DESK TELEPHONES 
with dial, si ightly used but all tested working. 22 6 each fo • > or 42'6 per pair 
(10./-) P.O. RELAY COUNTERS, 4 digit. 31 x. tin.. 17 6 CI/-*. MIDGET 
ELECTROLYTIC CONDENSERS. WIRE ENDS, FOR TRANSISTORS 



All at 6il. each 
0-8uF 25 volt 
275 volt 
150 volt 
64 volt 
150 volt 
2-5 volt 



lu.F 
2ilF 
4u.F 
4[iP 
64u.F 



16 (iF 
30 nF 
BOliF 
lMiJtF 
181J.F 
ELECTROLYTIC Can Cond. 



All 9(1. each 

2u.F 330 volt 
10u.F 25 volt 



At 1/- each 
16aF 250 volt 
■ 10 volt 




16 volt 
10 volt 

6-4 volt 

6 volt 

4 volt 
300 + 100 ■'. 100^ 18u,F 300v 5/- (1/-); 2000u,F 
15 volt 4- (lOd): 30y,F 250v Wire Ends 1/- C6d.>, 
TEST EQITPMEXT: MLXTITESTER: 20,0000 p. volt D.C. 4}in. x 31in. X 
Hin. D.C. voltS-5. 25, 50, 250. 500 and 2-5 K, A.C. -10. 50. 100. 500, 1000V. at 
10 OOOfi p. volt: D.C. current-0-60tiA, 0-2-SmA, 0-250mA: Res.-0-60KO , 0-6M Q , 
3Mn30Kn at centre scale: Cap: lOOaoF to 001;xF, 0-Olu.F to 0-lu.F. —20 
to -r22dBs, 67/6 f3,'6) with prods, batt. instructions. POCKET TESTER 
1000O per volt, 3Vin. x 21 in. x ljin. A.C. and D.C. Volts-0-12, 0-120. 0-1200 D.C- 
Current 0-lmA and 0-120mA. Res: 0-200.0O0O with prods, hattery and in. 
structions 35/- (1'6). 

V WEI. Mi;TEK:0-lmA. clear, plastic, precision lira. sq. 23'- (1/6). 
R.F. SKJNAL (,LMU A IOR, MODEL TE'iOI). 814.14.0. 
VACUUM TUBE VOLTMETER MODEL TEK, £1414-0- 
VALVE VOLTMETER MODEL TE40, £17.0.0- 
OSCILLOSCOPE MODEL TO!, SS2.14.0. 
(iRID DIP VOJ.TMK'I'KRS, MODEL TE 15, £12.0.0. 
(Ail above fully described in June Practical Wire/ess— Part P. & P. 5/- each). 
SWITCHES; standard Togsle. metal. 250v 2A. One hole fixing: SPST 2(3. 
SPDT3/9 DPST ?.!-. DPDT3/3, SUB-MIN slide type DPDT 1/6 each. Small 
DPDT. 3 way. centre "otf" lv9. Reed magnetic on 1 off 1.' 9 (7d, each, all types) 
SEMI-CONDUCTORS, ETC. All fully tested genuine guaranteed. 
TRANSISTORS: AC 107 3/-; AC126 2/-1 AC12B 2'-: ACY19 3/9; AF115 3/-: 
AF116 3, 1 -; AF117 2.'9: BCY415--: BFY18 3-; BSYfi r ) 2/6l 38Yil5A.3/-; GET113 
2 .'6; QET5S7 8/6: OC26 5'6; OC23 5/-: OC44 1 6: ODiS 1'6 : OC70 2/3: OC71 1/6: 
OC72 2 hi OC73 2r3; OC75 2.'-: OCB1 2 -: OCaiD 1 6l OC^2D 2 3; OC139 26: 
OC140 3-: HC169 3'6: OCI70 22: OC171 2)2; TK22C 16; 2N706A 3'-; 2N743 
4/6; 2N753 2,6. 

DIODES: OA5 1'6; OA9 1/8 ; OA81 1'6: OA85 1/6 : OA182 1/9 ; Gon. purpose 1/-. 
SILICON DIODE RErilFIERS: 750mA SERIES; BY100 000 piv 2/6; 400 
piv 1'9: 200 piv 14. SIX AMP. SERIES : BYZ13 300 pi v 3/6 :BYZ12 600 piv 4/6: 
BYZH900piv5'-: BYZ10 1200 piv 5/6- MULLARD STACK F.W. BRIDGE 
12A 100 piv 39 6. THYRISTORS :5 Amp series. 100 piv 7.6: 200 piv 9.-: 300 piv 
106; 400 piv 18F- lOAmp Series: 50 piv 10/-; 100 piv 12/-: 200 piv 16/-: 400 ptv 
20 '-. (On all semi-conductors. 7d. up to 3, 4 to 11, './-; 12 and over post and 
packing paid.) 

TRANSFORMERS: Output: 30 SW. TOOOil imp. for 6V6 2/6(1/-); Sub-min. 
iin. x iin. x '/,, in. Output: 30 for OC72 etc., and Driver 2/6 each (6d.) Step- 
down. 110'240v, 40W shrouded with fuse, 106 <$H. AERIALS: Car types. 
5 sec. retractable, vandal-proof loo kable with keys, highly suitable Minis 
(and all other cars) as only 8£in. under wing, complete with lead, plug. etc. 
27'6 (2,6). Motor-driven (12v), 5 section £7.10.0 (5 -). Telescopic 6 ex, 5(in. 
to'22in. for motor cycles, fitted swivel, ideal for F.M. and transistor sets 
5/- (1M. VIBRATORS: 12v. 4 pin non-synch S/6; 6v, 6 Or 7 pin, synch, 10/- 
(l/-).MAI\SNEON TESTER: Fly leads 2/- (Td.). PLUGS AND SOCKETS: 
Standard screened Jack plug, screw connection. 2/9: plastic body 2'-. 
Screw panel mtg. Socket for either, 1/6 (all 7d.). Screened lead-coupled 
phono plugs with block, 2'- (Td.). Phono plugs. 9(1. 3-5mm, min. Jack plugs 
or sockets. 1/- each (fid.) <Dozen may be assorted, of these items, sent post 
paid ) V ALVEIIOLDERS: B7G and B9A, 6(1. I'ach (moulded); Ceramic for 
813. Si- each (7d.) * OL. CONTROLS: Morgan 1 Meg., no switch, Iin. dia. 
spindle Iin. i,'6. Ganged 200k Lin, + 1 Megf.-loer, D.P. switch, concentric 
lon£ spindles, 4'6 Clod.), MOTOR: 230v. Varley. l/24th hp 230V. Spindle 
9/10in. x 3/16th in. 2500 rpm 10/- (2/-). 

FELSTEAD ELECTRONICS 

<P.W.8> 

Longley Lane, Gatley, Cheadle, Cheshire. 

Terms : Cash witb order only. No COD. MINIMUM ORDERS/- + P & F. Money 
refund guarantee if goods returned perfect within seven days of despatch. 
Postage and packing charges are shown above in bracket after most items: 
where NOT indicated, charges are 1/- on orders to 5/-, 2/- for 5/1 to 10/-. 3/- 
for 10/1 to £2, 4,'6 for over £2 to £4.19.11. Order value £5 and over sent p. and p. 
paid, UNLESS OTHERWISE SHOWN ABOVE. These charges apply to G.B. 
only. Elsewhere air or surface mail charges should be added. Please allow 
5 days for cheque clearance. 

REGRET NO LISTS NOR CALLER SERVICE AVAILABLE. 



217 






Practical Wireless Classified Advertisements 

The pre-paid rate for classified advertisements is l/6d. per word (minimum order 18/-), box number l/6d 
extra. Semi-di splayed setting £4, 12s. 6d. per single column inch. All cheques, postal orders, etc to be 
made payable to PRACTICAL WIRELESS and crossed "Lloyds Bank Ltd." Treasury notes should 
always be sent registered post. Advertisements, together with remittance, should be sent to the Advertise- 
ment Manager, PRACTICAL WIRELESS, George Newnes Ltd., 15/17 Long Acre, London, WC2, 
tor insertion m the next available issue. 



METAL WORK 



METAL WORK: All tvpes cabinets, chassis 
racks, etc.. to your specifications. PH1LPOTTS 
METAL WORKS LTD., Chapman Street, 
Loughborough. 



TAPE RECORDERS, TAPES, Etc. 

TAPES TO DISC— using finest professional 
equipment 45 rpm— 18/-. S.A.E. leaflet. 
DEROY, High Bank, Hawk Street. Carnforth. 
Lanes. 



MISCELLANEOUS 

ELECTRONIC sound and musical devices 
required for exploitation. Adequate finance 
available. Projects developed to pre-production 
si age required. Royalty payments guaranteed. 
Details only Box No. 74, 



— ELECTRONIC MUSIC? — 

Then how about making yourself an electric 
organ? Constructional data available- 
full circuits, drawings and notes! It has 
5 octaves, 2 manuals and peflals with 24 
stops — uses 41 valves. With its variaole 
attack you can play Classics and Swin?. 

Write NOW for free leaflet and further 
details to C. & S., 30 Maude Street, 
Darlington, Durham. Send 3d. stamp. 



SERVICE SHEETS 



SERVICE SHEETS, RADIO, TV. 5,000 
Models. List 1/6. S.A.E. Enquiries. TELRAY, 
11 Maudland Bank, Preston, Lanes. 



c. a- a. 

SUPPLIERS 

SERVICE SHEETS 

Only 3/6d. each, plus S.A.E. 

(Uncrossed P.O.'s please, returned if 
service sheets not available.) 

71 BEAUFORT PARK 
LONDON, N.W.11 

We have the largest supplies of 
TV Service Sheets only, by return of 
post. Please state make and number. 

Mail order only. 
218 



SERVICE SHEETS 

(continued} 



RADIO, TELEVISION over 3,000 models. 
JOHN GILBERT TELEVISION, lb Shepherds 
Bush Rd., London W.6. SHE 8441. 

SERVICE SHEETS. RADIO. TELEVISION, 
TAPE RECORDERS, 1925-1968 by return 
post, from 1/- with free fault-ftndine guide. 
Catalogue 6,000 models 2/6. Please send 
stamped addressed envelope with all orders/ 
enquiries. HAMILTON RADIO, 54w London 
Road, Bexhiil, Sussex. 



SERVICE SHEETS (75,000) 4/- each: please 
add loose 4d. stamp: callers welcome; always 
open. THOMAS BOWER, 5 South Street, 
Oakenshaw, Bradford. 



EDUCATIONAL 



CITY & GUILDS (electrical, etc.) on "Satis- 
faction or Refund of Fee" terms. Thousands of 
passes. For details of modern courses in all 
branches of electrical engineering, electronics, 
radio, TV., automation, etc.. send for 132-papre 
Handbook— FREE, B.l.E.T. (Dept. 168K), 
Aldermaston Court, Aldermaston, Berks. 



BECOME "Technically qualified" in your 
spare time, guaranteed diploma and exam, 
home-study courses in radio, TV servicing and 
maintenance. T.T.E.B., City and Guilds, etc.: 
highly informative 120-page Guide— free. 
CHAMBERS COLLEGE (Dept. 857K), 148 
Holborn, London, E.C.I. 



SITUATIONS WANTED 



A YOUNG ELECTRONICS enthusiast ts 
looking for a position as a trainee technician 
in Radio, T.V. etc. Prepared to work hard. 
Please reply Box 79, 



SITUATIONS VACANT 

TV and Radio. A.M.I.E.R.E., City & Guilds, 
R.T.E.B. Certs., etc, on "Satisfaction or Refund 
of Fee' terms. Thousands of passes. For full 
details of exams and home training Courses 
(including practical equipment) in all branches 
of Radio, TV, Electronics, etc. write for 132- 
page Handbook — FREE. Please state subject. 
BRITISH INSTITUTE OF ENGINEERING 
TECHNOLOGY (Dept. 137K), Aldermaston 
Court, Aldermaston, Berks. 



EDUCATIONAL 

(continued) 



RADIO OFFICER training courses. Write: 
Principal, Newpcrt and Monmouthshire 
College of Technology, Newport, Mon. 



RADIO OFFICERS see the world! Sea-going 
and shore appointments. Trainee vacancies in 
September and April. Grants available. Day 
and Hoarding students. Stamp for prospectus. 
Wireless College. Colwyn Bav. 



TRAIN FOR SUCCESS 
WITH ICS 



Study at home for a progressive 
post in Radio, TV and Electro- 
nics. Expert tuition for I.E.R.E., 
City & Guilds (Telecoms and 
Radio Amateurs") R.T.E.B., etc. 
Many unique diploma courses 
incl. Colour TV, Electronics, 
Telemetry & Computers. Also 
self- build kit courses— valve and 
transistor. 

Write for FR1IE prospectus and find out 

how ICS can help ymi in your career. 

ICS. DEPT. S41. INTERTEXT HOUSE, 

LONDON, SW11 



SITUATIONS VACANT 

(continued) 

RADIO and tape recorder testers and trouble 
shooters required. Canteen, excellent rates of 
pay. 8.00 a.m. to 5.00 p.m. 5-day week. 
Elizabethan Electronics Limited, Crow Lane, 
Romford, Essex, Phone: Romford 64101, 



ENGINEERS, A TECHNICAL CERTIFI- 
CATE or qualification will bring you security 
and much better pay. Elem. and adv. private 
postal courses for C. Eng., A.M.I.E.R.E, 
A.M.S.E. (Mech. & Elec), City & Guilds. 
A.M.I.M.I., A.I.O.B., and G.C.E. Exams. 
Diploma courses in all branches of Engineering 
— Mcch., Elec, Auto., Electronics, Radio, 
Computers, Draughts., Building, etc. For full 
details write for FREE 132 page guide: 
BRITISH INSTITUTE OF ENGINEERING 
TECHNOLOGY. (Dept. 16yK), Aldermaston 
Court, Aldermaston, Berits. 



SITUATIONS VACANT 

A Vacancy exists for a young man aged 1 8 years or over, who 
possesses some knowledge of Transistor Circuitry and Fault- 
Finding. Further "on the job" training will be given in the 
field of Telecommunications. 



Please apply to Personnel Manager, 
Cambridge Works Ltd., Haig Road, Cambridge. 
TeL Cambridge 51351 Extn 327 



SITUATIONS VACANT (continued) 



Radiomobile 

BRITAIN'S CAR RADIO SPECIALISTS 

have a vacancy for a fully experienced 

SERVICE 
ENGINEER 



The successful applicant will be employed in our Main 
Service Workshop repairing: — 

Transistorised and Valve Operated Car Radios 

Car Tape Recorders 

Coach Radio and P.A. Equipment 

and also in our Service Garage on installation work and 
the servicing of equipment already fitted to vehicles. 

After gaining considerable knowledge of our products, 
duties, in the future, may be extended to include mobile 
Field Service work. 

This position carries a good commencing salary together 
with above average fringe benefits. 

Applications should be made in writing to: 
The Personnel Manager 

RADIOMOBILE LIMITED 

Goodwood Works 
North Circular Road 
London N.W.2 



A sue5iDuwY a* 



a 



SMITHS KMCXJSTRrES LIMITED 



WANTED 




WANTED 


WANTED, Service Sheets for Televisions 
(older models preferred) also sheets for 
Transistors, Tape Recorders. Any quantity 
State price. Mr. CARANNA, 20U High 
Road, East Finchley, N.2. 


VALVES WANTED, brand new pooular 
ypes boxed. DURHAM SUPPLIES (C), 
175 Durham Road, Bradford 8. Yorkshire. 


WANTED NEW VALVES, televisions, radio- 
grams, transistors, etc. STAN WILLETTS, 
37 High Street, West Bromwieh, Staffs. Tel.: 
WES 0186. 


WE BUY New Valves, Transistors and clean 
new components, large or small quantities, all 
details, quotation bv return. WALTON'S 
WIRELESS STORES, 55 Worcester Street, 


Wolverhampton. 








WANTED NEW 
VALVES ONLY 

Must be new and boxed 
Payment by return 

WILLIAM CARVIS LTD 
103 North Street, Leeds 7 


WANTED: Popular Brand New Valves. R.H.S., 
Stamford House, 538 Great Horlort Road, 
Bradford 7. 


DAMAGED Avo Meters, Models 7 and 8, 
Damaged Meggers, any quantity. Send for 
packing instructions. HUGGETT'S LTD., 
2/4 Pawson's Road, West Croydon. 



WANTED 

(continued) 



WANTED: New valves, transistors etc.; state 
price. E.A.V. Factors 202 Mansfield Road, 
Nottingham. 



WE BUY New Valves and Transistors. State 
price. A.D.A. MANUFACTURING CO.. 116 
A 1 fret on Road Nottingham. 



COURSES 



CITY OF BIRMINGHAM EDUCATION COMMITTEE 

MATTHEW BOULTOX TECHNICAL COLLEGE 
DEPAHTMENT OE ELECTBtCAL ENtUNEERLSCl 

Sherlock Street, Birmingham o 

FULL-TIME COURSE I® RADIO, TELEVISION 
AND ELECTRONICS 

The proposed courwt! is intended for youiiR; men who 
Are employed in or are intent en making a career in the 
KadiffTtlevlfimWElectronto Industries, particularly to 
the Held of servicing. 

The i nurse will be of 9 months' duration, starting in 
September lyri-S, ami ™:ll load i , ' vamiii;ii i'ih ~'jM I iv 
the C.O.L.l. and E.T.E.B. 

Further details and application forms may be obtained 
trom the Head oi OepartmenL. 

E. L. RUSSELL, 

Chief Educutivn Officer. 



TRAIN AS A 
TELEVISION 
TECHNICIAN 

Two year Full-time courses leading to: — 

(1) Radio and Television Servicing Certificate 

(2) CoSour Television Servicing Certificate. 

( 3) Closed Circui t Studio Tech nicians Diploma. 

Courses start 16th September 1968. 

Further information obtainable from HEAD 
OF ELECTRICAL ENGINEERING DE- 
PARTMENT, College of Technology, 
Tavistock Road Plymouth. 



BOOKS & PUBLICATIONS 



AUDIO. America's foremost journal. Year's 
subscription 50/-. Specimen copy 4/6. All 
American radio journals supplied — list free. 
WitJen(Dept.40), 61a Broadway, London E.I 5. 



SURPLUS HANDBOOKS 

19 set Circuit and Notes ,, .. 5/5 p/p 6d 

1155 set Circuit arid Notes ,, .. 5. Ejivnor. 

H.R.O. Technical Instructions .. 4/6 p/p 6d 

38 set Technical Instructions, . .. 416 p,'p 6d 

46 set Working Instructions . . . . 4/8 p/p 6d 
88 set Technical Instructions, . .. 6/-p,'p6d 
BC.221 Circuit and Notes . , . . 4/6 p/p 6d 

Wavemeter Class Tech. Instr. . . 4/6 p/p 6d 
IS set Circuit and Notes .. .. 4/6 p/p 6d 

BC.1000 (31 set) Circuit and Notes . . 4/6 p • p fid 
CR.100/B. 28 Circuil and Notes .. 9/6 p/p 9d 
R. 107 Circuit and Notes .. .. 6/- p/p 5d 

AR.88D Instruction Manual 16/- p/p 1/6 

62 set Circuit and Notes , . . . 5/5 p/p 6d 

Circuit Diagram 4/- each post free, R.1 116; A 
R, 1224/ A, R.1355, R.F. 24, 25 and 26, A. 11 34 
T.1154, CR.300, BC.312. BC.342, BC.348J, BC.348 
(E.M.P.). BC.624, 22 set, 
52 set Sender and Receiver circuits 7/6 post Free 

S.A.E. with all enquiries please. 
Postage rates apply to U.K. only. 

Mail order only to: 
INSTRUCTIONAL HANDBOOK 

SUPPLIES 

DEPT. PW, TALBOT HOUSE. 

28 TALBOT GARDENS, LEEDS 8 



219 



RECEIVERS & COMPONENTS 



MINIATURE SCREENED MICROPHONE 
TRANSFORMERS (Plessey). I/p. 10 to 
1,000 ohms, o/p Z 100k to 2-5 megs. Primary 
centre tapped. 6/6 each, 5 for £1. P. & p. 2/-. 
AUTO TRANSFORMERS, o/p 100/1 lOv. 
300w. r/p 200/10/20/30/40/50. 37/6. P. & p. 4/-. 
150w £1. 



Hill Street 



J. DENBY 
. Haworth 
Yorkshire 



Keighley 



SUPERIOR QUALITY NEW RESISTORS 

Carbon flhn Low noise High stability 

Power range scries per dos per 10 

JW 5% 5-Ifi to330kO E24 1/10 14/6 
iW 10% lflto4-7Jl K12 +*d. per resistor 

iW 10% 4-7C1 tnlOMQ B12 1/9 13/6 
JW 6% 4-7 a tolOSffi KM '2/2 17/- 
1W 10% 4-7 a to 10MQ E12 3/3 25/10 
1/6 per 100 less in 100's oi one ohmie value 
FIjEASE state ycrar choice of values. 

QUALITY CARBON SKELETON FRE-SETS: 

iooQ.25on,500B.ikn,'ik£i,Jakfi.skn,iofcn, 

20kO r 'JSk(J,50kn.lOOsiR,250kD.500kQ,lMD, 

2M0.2-5MQ, 5MQ, 10MH. 

Available In horizontal or vertical mounting l/-each. 

LOW COST VOLUME CONTROLS: 100 n to 10MQ 
lin 8/3 each. 5kO to 5MB log 8/3 each. 

CERAMICS; 100, 220, 470, 1000, 2200. 470 OpF, 
500Y 5d. 0-OOS, O-01, 0-02, 0-05[iF 50V 64. 

ELECTKOLYTTCS: S, 10, S!5, SOpLF 10V., 5, 
10 [it' 25V 94. 100, 200{iF 10V.. 25, 50 at" 25V 1/-. 
Sub-mln Mullard C42S range: all values In stock. 
Large or small orders detpatehrd same day. 
EVERYTHING BRAND NEW . NO 'SDEPLTJS' 

Send 1/- /or our analogue containing data on 200 
up-to-date semiconductors available from stock, at 
welt a* many other components, also transistor equival- 
ents taMr. Invaluable to ever]/ serious experimenlet and 
designer. 

DISCOUNTS: 10% ner£3, 15% oi-er £10. 
Post and Packing: U* under £\,jree orer £1 

ELECTRO VALUE 

S MANSFIELD PLACE ASCOT BERKSHIRE 



RECEIVERS & COMPONENTS 

(continued) 

BARGAIN PARCELS of new surplus Elec- 
tronic Components, 3/-, 5/-, 10/-, post free 
DOLPHIN ELECTRONICS, 5 Pooles Way, 
Briar Close, Burntwood, nr. Lichfield. 

150 NEW ASSORTED Capacitors, Resistors, 
Silvered Mica, Ceramic, etc Carbon, Hvstab, 
Vilreous, 1-20 watt, 12/6 Post Free, WHIT- 
SAM ELECTRICAL, 18 Woodrow Close, 
Pcrivale, Middlesex. 



BRAND NEW TELEVISION TUBES 

2 YEAR GUARANTEE. HUGE RANGE 

12* £3; 14" £4.15.0; 17* £5.15.6 
19" £6.17,6, etc., etc. Carriage, etc. 12/- 

Also British and Telefunkeri valve lists! 
PHILIP H. BEARMAN, 6 Potters Road, 
New Bamet, Hertfordshire. Tel. 449/1934 



QUALITY NEW VALVES 

Guaranteed six months. Posted. 



DAKiXi 8/8 KCHSl 5/- ' ET.84 



Ul-'llli 
DK92 

UK-: 

mm 

DLon 



6/8 
6/fi 
~i- 
3/3 
71 



FAHOS0 5/3 
EMFK9 5/6 



BCLS0 8/9 EYS8 
EC 1,82 6/- EZ80 

4/8 ' EZ81 

fi/- PCC84 

6/- POC89 

2/- ' ~ 

3/0 

2/8 

8/ 

6/ 



[■: f*o 

El-'S5 

Et - si; 

EF91 

RI-'US 
KF95 
F.F1M 

KV 1>4 



i'Ct'Si) 

PCL83 
PCL84 7/3 

PCI>85 8/- 



Pl.:tii 
PL81 
PYlin 
PY81 
FY 53 



8/- 
7/3 
S/S 
5/3 
6/- 



UABCS0 6/9 
TJBP89 6/3 
TJCH81 8/3 
TICI.82 8/6 
TTL84 



L Y «3 



s/e 

5/- 



8/3 

2/6 
3/- 
3/- 



SEMICONDUCTORS 
Guaranteed twelve months. Post free. 
ACI07 4/- I JICI08 3/0 | OA90 1/4 j OC71 
API 14 5/2 RF-'ISO 7/6 I 0^35 6/8 OC75 
AF1I7 2/9 Itl'VoO 5/- 0C44 2/- OC33 
AF2S0 11/- I BY'100 3/6 | OC45 8/3 | OC170 

Lists valves, semiconductors, components, on request 

J. R. HARTLEY 

2 Waterloo Terrace 
Bridgnorth, Shropshire 



RECEIVERS & COMPONENTS 

(continued) 

CONSTRUCTIONAL AIDS 
—for you 

LEKTROKIT— complete chassis system. Gives 
that professional finish to home constructions. 
Send 6d. for complete price lists of our in- 
expensive electronic, components — including 
Sample Resistors— to : STUDENT ELECTRO- 
NIC SERVICES. 194 Regent Road, Salford 5. 



3-gang tuning capacitors 365pF per section with 

dual rfiiiuctiou. H-l and 18-1 ratio, antl backlash 

genre 9 lie 2 x 1J s l|in. long spindl* 7/8 each 

(brand new). 

2-gang tuning earMniltirs 375, 325pF 6-1 reduction. 

Set of 3 traiip-tstiir I.F. transformers with pin 

connection data. 10/- set. 

Mixed bag of silver mica and ceramic capacitors. 

appro*. 120, 8/6. 

Bag ot 100 80pF±W?i email silver mica 1 xiin. 

(brand new), 5/». Single tuned I.E. transistor 

transformers 2/- (470 6c /*). I) river and output 

transformers, suit QC81a etc. 1 watt rating 7/6 pair 

or 4/8 each. 

Sin. Ferrite rod aerials, no data, MW and LW, 5/-. 

Printed circuit t.nmnl : ftbreRlMs, 4x5 x l / u . 1/8 each: 

tufnol, 2 x Sin., 4 for 1/-; f s 4 Jin., 4 for 9d, 

Transistor CWMiton, H-inil-M 50VW, 3/- do*. 

ElectrQlj-tk-s: 2inrd, 6VW, 4d.; 4mFd, 64VW, 64.; 

5GmKd,'BVYY, 81; lOOmFil, 6VW, Bd.; lOOmFd, 

9VYV, lOmFd, 12VW. 8n.; ICSOml-'d, 1'JVW, Sfl.; 

350 in I'M, 9VW„ 9d.; 40 On o I'M, 15 VW, l/-;500mF(l, 

9VYV* 96. 

BY1000 rectifiers, «00 p.i.v., 750mA, brand new, 3,'-. 

Double gang pots. 250k - 250k log, 500k +500fclili, 

loiisr ^jiiMillt?", new, 8/- each. 

5k log pots, with tl/n switch, 3/-. 

Microti knJc radios sold out, 

S.A.E. for lists. Postal service only. 

A. J. H. ELECTRONICS 
(G8A, Q.N.) 

59 WAVERLEV BOAD, THE EEIT1I 
RU&BY. WAHWICKSHIBE 



NEW PRICES ON NEW COMPONENTS 



DISCOUNT- 

10% over £2. 
1 5% over £5. 



ELECmOI/VTIC CAPACITORS (Mullartl). 

-10% to +50%. 

Subminlaturr: (All values in ttF) 
4V 8 3S 64 135 250 400 

6-4V 6'4 25 50 100 200 330 

10V 4 16 32 64 125 200 

16V 2'5 10 20 40 80 125 

25V 1-8 6-4 12-5 25 50 80 

40V 1 4 8 16 32 50 

64V 0-64 2S 5 10 20 32 

Price l/6d. l/3d. l/2d. L- 1/W. 1/8<I. 
Small (All values in nF) 

4V 800 1250 2000 3200 

6V 640 1000 1600 2500 

10V 400 640 1000 1600 

16V 250 400 640 1000 

25V 160 250 400 640 

40V 100 160 250 400 

64V 64 100 160 250 

Price Z',W 3'4d 4/2d 5/2*1 

Large (All values in ij.F) 

10V 2000 3200 5000 10000 16000 

16V 1250 2000 3200 6400 10000 

25V 800 1250 2000 4000 6400 

40V 500 800 1250 2500 4000 

64V 320 500 800 1600 2500 

Price 8'3d 9/Bd 18,'9rt 19/9d 23/3(1 
Clips 1/- l/2d 1/gd l/3d l/4d 

POLYESTER CAPACITOKS (Milliard) 
Tubular: 10% 180V: 001. 015. 022|iF, 7d. 
0033. 0-047 nF. 8d. 0068. lu.F. 9d. 0-15[tF, lid. 
0-22aF, 1 -. 0-33-aF. 1.3(1, STiiF. 1 (W, 6WuF. 
2/3d. 1-jtF, 2/8(1. 

400V: 1,000, 1,500, 2,200. 3,300. 4,700pF, 6d. 
6,800pF. 01. 0-mr,. 0-022 riF. 7d. 033;xF. 8(1. 
0047U.F. 9d. 0068, OlitF. lid. 015U.F. 1/2*1. 
O-ffisjtF, 1/6. 0-33UP. S/3d. 0-47U.F. 2/gd. 
Modular, metallised. P.C. mounting. 20%, 
250V: 001, 0015, 0022nF, 7(1.0033. 047[iF, 8<). 
0-068. 0-1 (J.F, 9d. D-15U.F, 11(1. 0-22 ^F, 1,'-. 0-33|j.F. 
l/5d. 47fxF, l/8d. 0-6«tiF. 2/3d. IftF. 2/9d. 
POLYSTYRENE CAPACITORS: 5%. 160 V 
(unencapsulated); 10. 12. 15, 18. 22, 27. 33, 39. 
47, 56, 68. 82, 100. 120, ISO. 180. 220, 270. 330. 390. 
470. 560. ijljfi, 820|il'\ 5d. l.'M.fl. 1,500. :'. 2ii0pF, 6(1. 
3.300, 4,700. 5.600pF. 7d. 6,800. 8,200. lO.OOOpF, 
8d. 15.000. 22.000pF. 9d. 

1%, 100V 1 encapsulated! : 100. 120, 150. 180, 220, 
270, 330, 390. 470, 560, 680. 820pF. 1/-. 1,000, 1,200, 
1,500, 1800, 2.200, 2,700, 3,300, 4.700pF, 1/8(1. 5,600, 



0,1:01). ft, 200. lii.uon, 12,0n0. 15,000pF, l/6d, 18,000. 

22,000. 27,000, 30,000. 39.0O0pF. l/9d. 047, 0-056jjF, 

21-. 0068, 0082. 0-ly.F, 213d. 012u.F. 2/9d. 15. 

0-ietiF. 3/-. 0-22HF. 4/-. 0-27, 0-33 U.F. 5/-. 39 nF, 

5/9d. 0-47U.F. 6/3. 

PdTFNTIO.METIIRS (Carbon), miniature, 

lin, x Jin. spindle. Lin; lOOu to 10MQ, Log: &KS1 

to 5Mfl. 2/3*1. 

SlliKKO POTRVTIOMETERS (Carbon). 

Matched tracks. 2 in. x ;in. spindle, 20KQ to 

2M fi . Lin. and Log. 8/- (with switch. 10/6). 

SKELETON PRE-SET POTEMTOMETEKS 

(C'arl)on): Lin. 100 fi to 5Mfi. Horizontal and 

vertical F.C. mounting. 

Miniature (0 3W). IS-. Submln. (0 1W). lOd. 

RESISTORS (Carbon FilmJ 

High stability, very low noise. 

5% Range; 4-7 fi to 1MQ (E24 Series). 

JW, 2d. ea., over 99, l|d. ea. 

(100 off per value. 13/9d). 
%W, 2id. ea., over 99, 2d. ea. 

(100 off per value, 15/6d). 
10% Range: !0H to 10MQ (E12 Series). 
iW, 1 id. ea., over 99, lid. ea, 

(100 off per value. 12/-). 
|W, 2d. ea., over 99, l|d. ea. 

(100 off per value, 13/9). 
SEMI-( OMJl (TORS: OA5, OA81. l/6d. OC44, 
2f-. OC4S. l;gd. OC71, OC72. OC73. OC81. OC81D, 
OC82D, OC170. OC171, 2/3d. OC140, AF115, AF116, 
AF117, 3/-. 

Also entire current Newmarket range. 
SILICON RECTIFIERS: 5A. 170 P.I.V., 2/9d, 
400 P.I.V., 3-. 800 P.I. V.. 3 '3d. 1,250 F.I.V., 3/9d. 
1,500 P.I.V. 4/-. 

JACK PLUGS (iln.): Black, white, yellow, 
green, red or blue covers. 2i3d, 
Screened (heavily chromed). Standard, 2/9d. 
Side-entry version. 3,3d, 

JACK SOCKETS (lin. i'lug) : Chrome facia nut. 
Make/Make, Make/Break, BreakjBreak, or 
Bi i-ak.'Make, panel insulated. 2/9d. 
FKIM fc;l) CI It CC IT IIUAH1) (Vero) 
0-15in. Matrix; 3t x 2Jin.. 3/3d. 5J x 2iin.. 3/1 Id. 
31 x 3iin., 3/lld. 5 x 3iia„ 56d. lin. Matrix: 
33 x 2} in., 4,'-. 5 x 2iin.. 4/6d. 31 x 3Hn.. 4/6d. 
5 x 3? in., 5/3d. 

Send S.A.E. for May 1968 Catalogue. 



X ICYVMAR KET P AC KA GED 
AUDIO AMPLIFIERS 

(Very low quiescent currents) 

FC1: 9V. ISOmW into 40 Q. 1 5k Q mput. 

Sens : 50mV/50mW. 2 x 1 x tin. 30/-. 

PC2: 9V. 400mW into 150. lkfi input. 

Hen?: lmV/SOmW. 21 x IS x Jin. 37/6. 

PC3: 9V. -JOOmW into 15 n. 2-5kfi input. 

Sens : SmV/SOmW. 21 x 11 x J in, 37/6. 

PC4:9V. 400mW into 15 fi. 220k (1 input. 

Sens: 150mV/50mW, 21 x li x Jin. 37/6. 

PC4L: 9V. 800m W into 8(3. 2k li input. 

Sens: 2mV/50mW. 2J x 1! x Jin. 41/3. 

PC5: 12V. 3W into 311. lkfl input. 

Sens: omV/SOOmW. 51 x li x i in. 75/-. 

PC7: 9V. IW into 8fi. lkD input. 

Sens : 5mV/50mW. 3 x li x Jin. 51/-. 

PC7/12; 12V. IW into 150. lkfi input. 

Bens: SmV.'SOmW. 3 x 1 x 3in. 51/-. 

PC9: 9V. Impedance match amplifier. 1M fi input. 

600 O output. 15m V out for IV in. 22 6'I. 

FC10: 9V. Tape-replay pre-amplifier. 150 a input. 

3-3kOout. 150mV ilkt-i out, for lr,rnV in through 

0-5H. 17 dB bass boost at 70o/s. ao.'-. 

PCU: 14V. 5W into3fi. lksi input. 

Sens: 5mV,'500mW, 5i x If x Jin. 90/-. 

P«t\YEK I NITS (lor above ampliflcrs) 

PC101: 9V/100mA. 200-2SOV a.C, 

For: PCI, 2, 3, 4, 4L, 7, 9. 10. 30/-. 

PC106: 12V/500mA. 2O0-250V a.C. 

For: PC5, PC7/12. 43/6. 



INTERCOM/BABY ALARM 
(Tran s i storls i ■ < i ) 
Master, with volume control/switch, and 
sub in elegant cream plastic cabinets, 
4 x 3 x II in., and 50ft cream lead with plugs. 
Exceptional reproduction and sensitivity. 
Facility for calling with units switched off. 
Suitable for desk or wall mounting. 
Complete outfit. £3. Battery 26(1- 
P. & P. 3/6d. (Regret no order discount). 



MINIMUM OR HER VALUE 5/- 

C.w.o. Post and Packing l/-. 

DUXF0RD ELECTRONICS (PW) 

Duxford, Cambs. {Sawston 3031) 



220 



RECEIVERS & COMPONENTS 

(continued) 




COMPONENTS -3 

POSTAL SERVICE 

* RECHARGEABLE 
BATTERIES 
(Bailed DEAC Xi-Cad) 

PP3 Ermlv.: l>v. 39/- (p * n 3/-c».) 

U-> Eiiuiv.: 1 .25 v. 35/9 <p 4 p '2/-ea.> 

U7 Eu,ulv.: 1.S6V. 14/6 iv x p 1/Sea3 

ITU Kqinv,: 1.25 v. 38/6 <p ft p 1/6 ea.) 

* NEW BARGAIN PACK 

lOf) Hi-stsh Keeitton?. 3d Silicon il taks (un- 
graded >, 8 Rectifiers (top hat) 15/- 

* ASSORTED RESISTORS — Hi-Ktftl), 3U0 off 

\l\ » P. 1/6 per order) C.W.O. 

S.A,E.for list of Industrial Component* 
for the Rome CoHntruetar, 

ELMBRIDGE INSTRUMENTS LTD. 

Island Farm Avenue, West Holesey, Surrey 



LHI|:1J 



EX GOVT.) 



Klii-Mill^ 



FAMOUS NO. 13 SET TRANS/RECEIVER 




■1 s M, 



Cavi 

bands, 1 1 valve "upcrhet 

f.ranBodvflr In el tiding .so 7 
m P-A. Power rcqs. T,T12v. 
I 1 H.T. rcc, 275v, H.T. 

transmit (JOOv, D.C. 

Slightly used 55/-. 

SeleeU-il comliUoii 85/-. 
All 19 set ancillary parts available. 
COLLIN'S {U.S.A.} REGETVEH 7 vali-esuperhct . (Int. 
Octal rates), Exceptionally stablt- lot t?SH. Prcquen- 
.- I -.1-12 Mc/s. Power required 2o0v. D.C. 
SOrnA. 12 v. AC 1-25 A. Excellent condition £12.0.0. 
No. 31 TRANSCEIVER. YHF 40-4 S Me/9. Tunable. 
HI><M,'4iv. balttiy operation. 70/-. 
No. SB TWO WAT RADIO. 40-42 Me/s, Crvstal 
controlled. 4 channel. 50/- each. 
B4.4 VHP RADIO TELEPHONE. S0-BC Mc/s. Crystal 
controlled. 12v. D.C. operation, £7,10.0, 
No. 68 TRANSMITTER RECEIVER, lffi-10 Mc/s. 
Tunable or I'ryFtal controlled. 12y, D.C. operation. 
£18.10.0. 

R.C.A. CBS TRANSMITTER RECEIVES. 2-8 Mc.'s. 
Complete station. Brand new. 12 or 24v. D.C. 
ope rat Ion. £18.10.0. 
Ho. 5S RECEIVERS. Few left. Used 
ITCrviceaWe). £7.10.0. 

TUBULAR STEEL TELESCOPIC AERIAL 
MASTS.aftft.4icctinTi70/-, 
83ft , m above with 12ft, whip 80/-. 
34ft, li uect.irm B0/-. 

MAKE YOUR OWN AERIAL MAST : 
8ft. fin., din. ilia, interlocking utecl xectlons. 
ooa make 35ft. mast). SO/- par section. 
NYLON SOY ROPES with seml-aii to matic 

: 33ft. 6/6; 50ft. 7/6; «0ft. 8/-. 
ROTARY TRANSFORMERS BY HOOVER. 
12v D C input. Output- 9807. D.C. at 125mA 
25/-, I2v. D C iLput. Output 490v. D.C. at 
i)5mA. 95/-. 

REJECTOR UNIT. For rejecting unwanted 
signal". Switched 4 ranges. 1-2-1(1 Me/a. 30/-. 
R.F. ANTENNA TUNER (A.T.U.). 100/80;40 
metres. 25/-. 

MOVING COIL HEADPHONES. Soft rubber 
eai pails. 18/8. 
D.L.R. BALANCED ARMATURE HEADPHONES. 
12/6. 

HEADSET WITH BOOM MICROPHONE. As used 
willi BS svt.22/6. 

MOVING COIL HEADPHONES AND MIKE 21/8. 
TRANSMITTER, 1-75-16 Me/s. 3 waveband Innahle. 
813PA Complete all valves, circuit. £7.10.0. 
POWER SUPPLY. 12t. D.C. input. 'iH6 and 1300v. 
D.C SliOniA output. Incorporating 230v. D.C, 80mA 
vibrator pack. Circuit. £7.10.0. 

All IteniH Carriage extra Mainland only. List giving 
frailer detalli of these and many other surplus bar- 
gains 2/-. S.A.E. all enquiries (Pleaae print clearly). 



A.J.THOMPSON (Dept.P.W.) 



'■RILING LODGE"', CODICOTE, HITCHIN, HERTS. 

Pnone:CODICOTE242 
lloure of husmessBfonday to Friday 8-E. Sat. 8-13. 
Prices correct at time of press but subject to increase. 



P.C.R. Rx 

These are a 6 valve plus rectifiers Long. Med. 
and S.W. Ri covering S.W. 6 to 18Mc;s SO 
to IS metres, they have internal speaker, 
sks for phones, tone control, Ae trimmer, 
and good slow motion drive supplied fitted 
with 200/250V mains P.U. Tested and ready 
to work, size 16 x 8in, front by lOin. deep. 
Good condition. 
Price: £8 10s. Od. plus 12s. 6d. carr. 

RECT UNIT TYPE 7 

Ii'P 20O/25OV 50c/S or 12v D.C. O/Ps 160v D.C. 
at 30tnA, 40v A.C. at 30mA. 12v D.C. at 300mA. 
fitted fuse, on off swt, Did lamp, terra strips, 
etc. Also spare vibrator. Ideal for small 
charger. New and boxed. 
Price: 25s. plus 7s. 6d. carr. 

Also in used condition 17s. 6d. plus 

7s. (M. carr. 

INDICATOR UNIT TYPE 95 

Contains CRT type VCR. 97 green screen, 16 
octal valves. CRT filament trans Focus. Brill, 
Gain controls fitted. Also Mu Metal shield 
slow motion dial, 2 x SOOpF tuning conds. 
lOGKefe standard crystal unit, slow motion 
drives and large number of other parts in 
good condition with outer cover. 
Price: £3 15s. Oil. plus 10s. carr. 

TEST SETS 261 and 266 

These are a portable test osc intended to 
work off 6v D.C. The 261 covers 175 to 305MC/3 
and the 2SG covers 95 to lHOMe/s. These units 
are directly calibrated, no Xtals are required 
and the O/P is modulated with var freq osc 
A small Ae system is supplied, and a 6v Vib 
unit is built into unit. 

Price: Either type£3 5*. Oil. plus 10s. carr. 
OR £6 per pair carr. paid. 

Rx UNIT TYPE ARR-2 

These are a small airborne Rx tuning the 
band 234 to 2o8Mc s and use valves 6AK5 x 3. 
8001 x 7 and 12A6 0?F. These have O.P for 
300 ohm phones, size 5 J x 4Jin. front, llin. 
deep. These Rx in their present condition 
are unsuitable for normal use. They can, 
however, be modified to tune the band 125 
to 150Mcis circuit diagrams and full modifi- 
cations are supplied with Rx in good condi- 
tion. A teat Osc or Sis sen is required to carry 
out the modifications. 
Price : £3 10s.- Qd. plus 6s. post. 

R.F. AMP No. 4 

This is the V.F.O. and P. A. section or the 
Army No. 53 Tx covering the freci range 12 
to 17'5Mc ; s in 4 bands and uses the following 
valves: Osc TT11, Buffer TT11. Driver 807, 
P. A. two 813s. Bias rect 6X5. Volt stab 
VSllOxS, 3 meters are fitted to monitor Grid, 
Anode and Ae current. Ae C/O relay is fitted 
and unit is intended to work into a dipole Ae, 
ext supplies of l.SKv, 400v D.C, 230v A.C. and 
12v D.C, are required. Unit can be operated 
with one 813 to bring IfP power down to 150 
watts. Supplied new and crated with circ. 
Price : £15 pins 20s. carr. 

V.F.O. section of above in used condi- 
tion with circ price £4 plus 10s. carr, 

ROLLER INDUCTORS 

For Ae tuning and loading, size of coil 2Jin. 
dia., Tin. long, approx. 48 turns with knob and 
counter dial. Ex equip. 
Price: 17s. 6d. plus 4s. Sd. post. 

465 Kc/s l.F. TRANSFORMERS 

Size is x U x 31 in. can be used in 19 set or 
P.C.R. ideal for improving gain and selectivity 
in old units. New and boxed. 
Price: 8s. 6<i. per pair post paid. 

POWER UNIT TYPE 311 

I/P 200, Z50v 50e. s. Oips + 300v at 250mA. — 130V 
at 40mA, 12v D.C. smoothed at 4 amps. The 
O/Ps are all fused and can be switched re- 
motely by relays in P.U. Supplied in good 
condition with outer cover and circ. This unit 
is the ground supply unit for the SCR. 522 
(BCG24/5 Tx/Rx). 
Price: £4 10s. 0d. plus SI carr. 

POWER UNIT KIT 

Complete kit of parts to build a 230v I P P.U. 
with the Tallowing O/Ps: SOOv D.C. smoothed 
at 140mA, 6-3v at 6 amps and 6 3v at 2 amps. 
Parts supplied as follows: H.T. trans. L.T. 
trans. Choke, 2x conds. 5U4. On/Off swt, Did 
lamp, fuse, valve holder, mains cable, con- 
necting wire and circuit. Al] you need is 
chassis. All parts are ex equip and in good 
condition. 
Price; £2 10s. Od. plus 8s. 6d. carr. 



TEST SET TYPE 219 

I/P 230v SOc/s this is a variable freq pulse 
generator covering SOOc.'s to lOKc/s in 2 ranges. 
The width of the G/P pulses can be adjusted 
from 5 to 0-5 y, sees. There is also a fixed width 
O.P pulse of 20 pl sec. The 0,'P can be switched 
to ^50, +10 and — lOv and is variable down 
to 1 Mil volt in steps of 10. By making an 
internal connection to the unit it is possible 
to obtain a 1 to 1 square wave and sawtooth 
waveforms. Supplied in good condition. 
Tested with circ and leads in transit case. 
Price: £5 10s. Od, plus 12s. 6d. carr. 

TAG BOARD ASSEMBLY 

This is a 26-way Tag Board fitted with the 
following parts: 17 1NS38 and Top Hat Diodes. 
These are rated 200v P.I.V. at 250mA, 2N414 
P.N. P. and 2N438 N.P.N, transistors, 7 1% 
resistors and 18 other small parts. All parts 
can be removed and reused. 
Price : 12s. 6d. plus 2s. 6d. post. 

POLARISED RELAYS 

These have two coiis of lgK ohm each, con- 
tacts 1 polec/o. with dust cover. Both contacts 
and magnet can be adjusted and moving 
contact will stay in either position. These 
can be put to use in the construction of a 
Scope calibrator and 50c/s square wave 
generator, A circ diagram and instructions 
are supplied with them. Ex American equip. 
Price: 10s. plus Is. 6d, post. 

MINIATURE UNISELECTORS 

Coil 600 ohm 50v, contacts 1 pole 11-way 
3-bank. made by Clare & Co., U.S.A. Ex equip. 
Price: 18s, 6(1, pluses, post. 

DIGITAL IND UNIT 

This is a digital indicator unit bu<l>; >nto a 
ISin. rack panel, 3Jin, high by 17in. deep. 
There are three low voltage number tubes 
plus one with special markings. These give 
numbers to 9, Jin. high and requires 6v, 
Each number tube has 10 lamps, each lamp 
has one 2N434 and one 2N1184 transistors 
which are mounted on plug-in boards. One 
board with 20 transistors to each tube. Size of 
each number tube 4in. long, llin. high and 
lm. wide. Extra tubes can be mounted side 
bv side. These were made in '63 by Sylvania 
U.S.A. for USAF, In very good condition. 
Price: £8 plus 10s, carr. 

Single tubes with transistor board and 
plugs price 50s. Od. plus 4s. 6d. post. 

POWER UNIT FLR-9 

lip 120v 50c/h O/Ps - 100 v D.C. at 8 amps. 
— 26v D.C. at 4 amps. 7 25v A.C. at 78 amps. 
These are a very elaborate P.U, made bv 
Bogue Elec. U.S.A. for the USAF in '63. All 
three O/Ps are stabilised and can be adjusted 
over limited ranges. Further details available 
on request. Supplied in very good condition. 
Price: £26 plus 30s, carr. 

POWER UNIT FLR-9 

I/P 120v 50c/s O/P lOv D.C, at 20 amps, the 
O/P is fully stabilised and can be adjusted 
from front panel over the range 3 to 12v at 
20 amps. O.P ripple at full load is less than 
10 MiJ/V. Made in '63 by Bogue Elec. forUSAF, 
Supplied in good condition. Further details on 
request. 
Price : £16 plus 15s. carr. 



MIN PANEL METERS 500 Ua scaled 1mA 2j 
OSSD 14/-, Whip Aes 12ft 3-section with base 
18/-, B.N.C. plugs and Sks 2/6 ea, 100ft insu- 
lated Ae wire with 3 insulators 10/-, llovoOc/s 
blower motors new boxed 28/-, Trans 230. nf) 
pria. sec 6v 1 5a twice new boxed 14/6, 12v la 
F.W. metal rect 6/-, Panel neon indicators with 
res for 230v good q ual i tv 3 Tor 7/6. Contro ] knob 
12 ass to fit 1 shafts 6/- or pointer knobs llin 
long 7/6 for 12, Large W.W. pots 25K 3in. dia. 
I shaft 6/-. Toggie swts 3 types as follows all 3 
for6/-: D.P. co. D.P. c.-ts biased one way. Single 
pole c/o. Top hat diodes type 1N538 2O0v P.I.V. 
at 250mA 6/6 per doz ex equip, Conds luP 400v 
block paper with clip modern make 3 for 6/-, 
( v.iid:-- 20uF 130v and ir>uP 1'iOv Tantalum new 
unused 21- ea, A.F. O/P trans Pria 10/60K sec 
800 ohm new 9/-. Meters 50Ua scaled in mini 
Rontgens 2iin proj 20/-. Small insulated test 
sockets to take 1.16 th dia. prod 6/- per doz, 
CV2247 Geiger Muller tubes new tested with 
circ 10/-. Conds 8uF 750v block paper 4 for£l. 
Relays 115v A.C. 2p cio will work off 230v 
through 2K ww res 5/-, U.S. Army Xtai boxes 
4i x6l x llin. hinged lid no holes 8 for El. Two- 
sided box lis 3x4iin. with 2 hinged lids 4 for £1 
(both types new). Lesdex swts 24v 6p 4w 3b 
small type 12/6, xtal unitsi00kcstandardll/6. 
All above post paid, 

SEND FOR FREE LISTS 



B. SLATER Esq. 

55 HANDSWORTH ROAD, SHEFFIELD S9 4AA 



221 



RECEIVERS & COMPONENTS 

(continued) 



STELLA NINE RANGE CASES 

Manufactured in Black, Grey, Lagoon or 
Blue Stelvetite and finished in Plastic- 
coated Steel Morocco Finish. The frame is 
of Dura with Aluminium end plates. Rub- 
ber feet are attached and there is a 
removable back plate with removable 
Aluminium front panel. 

LIST OF PRICES AND SIZES 
which are made to fit Standard Alio; Chassis 







4' 


6" 


71" 


Width 


Depth 


Height Height 


Keight 






£ e 


d Bad 


£ 9 d 


w 


81* 


10 


12 8 


14 6 


er 


41* 


11 


6 14 8 


16 6 


81' 


31* 


12 


6 18 


17 9 


Bi* 


er 


17 


i 116 


19 


WJ* 


71- 


1 3 


18 


1 11 9 


12*- 


3J* 


17 


e 119 


14 9 


121- 


Bi- 


1 £ 


3 17 


1 10 6 


12 i* 


er 
3i* 


1 8 


e i 14 o 


1 IS 9 


1«- 


1 


8 15 


17 3 


i*r 


9|* 


1 IS 


S 4 9 


8 7 


181* 


61- 


1 U 


1 17 


SIS 


181" 


10" 


1 19 


S 2 10 


2 17 e 


CHASSIS in Aluminium, 


Standard Sizes, with Gusset 






Plates 




Bites to fit Cases 


All 2J -Walla 




a d 




a d 


a d 


8*x3* 


5 8 


10' x 7- 


8 3 14' x 3* 


7 3 


6"x4* 


5 9 


12- x 3* 


8 9 14* x 9" 


14 6 


B'XS- 


6 6 


I'.r- ■ .r 


7 8 18- x 8" 


10 9 


8*x6* 


7 9 


12" x 8' 


10 9 lO'xlO 


" 18 






Post on all orders 3/-. 




Transistors Boards containing at least 12 Texas 


Transistors {mixed) plus diodes, + resistors, 4- 


condenaera. All lor 10/.. 


POST FREE. 




SCOOP. 


100 m 


xed condensers. All new hi packets. 


100 for 7/8. POST FREE. 





E. R. NICHOLLS 

Manufacturer of Electronic 
Instrument Cases 

46 LOWFIELD ROAD 
STOCKPORT, CHESHIRE 

Tel: STOckport 217$ 



FOR SALE 



SEE MY CAT. for this and that. Tools, 
materials, mechanical and electrical gear — tots 
of unusual stuff. This Cat. is free for the asking, 
K. R. WH1STON (Dept, PWC), New Mills, 
Stockport. 



yt/KAU 



/lett&^winm GREY1MMER 

f' o LHiH.KLf llimchpc. 



IMS Mr«e[ ipnyJtit COfttllflf id mj. fin« 
riHty durible «liy jniT.ru ipr* r . Mo irce bjkn( 
nlUblt irr flry. Q:u«. fclj. 



l(U , 



irll. 



It 51. Ol I{ J 

ia„.|M(it 

Jnclvtje: 

Zlrre Cfrrenrat* 

ClM, LcxoutT 

AtMfRHJ*Snfi 



SPECIAL Off Ed: I an plus optim! triniltrablt 
■Ji,p^n t rifr«f h,ndle („lue 5/.) lor IS/fl. cvriMt 
plld, Cho'c* of J J Mir-jpnr pills cooun liid or.- 

" r or iiL, !: 7 .| tUa ,, i Ijfclc. 

I Relic endole Cheque or crotlcc? P.O. for toul amount SOI 
VI 11/ A U Cept. 307a, E0GWARE ROAD, 

i u i\«n, PW , G lohpom, wo. 

1 W« luppfr otinr Gov«rnm»nt t>,p4r[mcntt, MimkJptl 
^ Audwtllu, Iniotutcl Hlo Le*(JJSS lnaLjim.il 
( ofli -we ui luppjy rw too. 
I Opir» jB d, r iHurdii/, Cloud Thurfdlf ifWnoonl 



RADIO KNOBS, llrr, dia.. *in. fittine. Black. 
3/- doz. inc. post. G4MH, 8 Townend, Golcar, 

Huddersfteld. 



FOR SALE 

(continued) 



Boxes of B.A. Nuts and Bolts, all Brand new 
and high grade machine cut items, invaluable to 
all Service men, experimenters etc. Bolts 
include 2.BA 4.BA and 6.BA up to 2" long, 
various heads, mainly brass, approx. 3 — 400 
items per box, our Special Price 7/6d. plus 2/-d. 
Post and Packing. WALTON'S WIRELESS 
STORES. 55a Worcester Street, Wolver- 
hampton, SiafTs. 

HALF PRICE OFFER. ELECTRIC SOLDER- 
ING IRONS. 220/240v. 40w. Plastic covered 
extension wire. Pistol grip handle which un- 
screws and fits over tip when not in use. Worth 
at least 30/-. ONLY 15/- plus 2/- p. & p. Send 
Cash or P.O. with order to: HARRISONS 
MAIL ORDER. 15 Pit Lane, Mountain, 
Quecnsbury, Bradford. Yorks, 

MONEY BACK GUARANTEE. 



HIGH GLOSS METALLIC 



HAMMERED ENAMEL' 
MAKES FANTASTIC 
DIFFERENCE TO PANELS 

— tar hundreds ol enthusiastic uteri. 
'CracKfe 1 pattern appears 

like magic on wood and , 

metal. So undercoat. Air ViUpfV BRUSH 
dries IS iiiin. to hard ^■'s^^^riD cddav ntj 
glossy finish. Heat, llijuld **^ UK af**" u " 
and acxat-ch-proof. Lt, and Dk. Blue; Bronze; Silver; 
Greco; Black. Send 10/- HOW for trial lot. Tin, Colour 
sample* and Instructions. Post tree. 

FINNIGAN SPECIALITY PAINTS, Dept. P.W. 
STOCKSFIELD, (Tel. 228D) Northumberland. 



MINIFLUX 4-Track siereophonic/mono- 
phonic record/playback heads. List 
Price 6 gns. — Special Offer 55/- each. 
MINIFLUX 4-Track stereophonic/ 
monophonic Ferrite Erase Heads. List 
Price £3.10.0. — Special Offer 32/6 each, 
or supplied together (one of each) at 
£3.17.6. SKN4 Hraclc stereophonic 
record/play heads for Transistor Circuits 
at 55 ■- each. Also available j -track and 
full-track monophonic Ferrite Erase 
Heads. All heads complete with technical 
specifications. Send S.A.E. for details. 
LEE ELECTRONICS, 400 Edgware Rd„ 
Paddtngton 5521. 



MORSE ?£ S D V E II 

FACT NOT FICTION. If you start RiOHT tou will be 
mailing amateur and commercial Morse wit bin a month. 
(Normal prop-ess to be expected.) 

Using scientifically prepared 3-speed records you 
automatically team to recognise tbe code RHYTHM 
without traiv, I at log. You can't help It, it's easy aa learning 
a tunc, 18 W.P.M. in 4 weeks guaranteed. 

For details and course C.O.D. ring, s.t.d, 01-660 2896 
send Sd. stamp for explanatory booklet to: 

G3CHS/F. 45 GHEEM LANE, PDRLEY, SURREY 



ELECTRICAL 



DONT MISS THIS OFFER 



British Made Electric Soldering Iron, 6 months 
Maker's Guarantee AND After Sales Service, 
30 watts 230-250 volts or 200-220 volts, state 
choice, supplied with over 10ft. of 3-core pvc 
flex. This is a quality iron at the ridiculous low 
price of ONLY 16/- - 1/6 P.P. SOUTH WEST 
SUPPLIES, 222 Fishponds Road, Bristol 5. 




20' 18/9 

30' 24/9 



DRILL 
EXTENSION 

^ LEADS 

Best quality 3-core cable used. Fitted with 
unbreakable rubber plug and socket in either 
1 3 amp,, 5 or 15 (state choice). Will also extend 
your vacuum lead, hedge trimmer, mower, etc 
SOUTH WEST SUPPLIES (Dept. PI) 
222 Fishponds Road, Bristol 5 



NEW RANGE BBC 2 AERIALS 

All U.H.F. aerials now fitted with tiltlnp; 
bracket, ajtd 4 element grid reflectors, 
i.oft Mounting Arrays, 7 eUimiiL. 37/6. 
11 element. 45/-. 14 element. 52/6. 18 
element, 60/-. Wall Mounting: with 
t ranked Arm, T element. 60/-. 11 element, 
67/-. 14 element. 75/-. 16 element, 82/6. 
.Mast M< hi n imp with 2in. clamp. 7 element, 
42/6. 11 element. 55/-. 14 element. 62/-. 18 
element, 70/-. Chimney Mounting Arrays, 
Complete. 7 element. 72/6. 11 element, 80/-. 
14 element. 87/6. 18 element. 85/-. Complete 
assembly Instructions with every unit. Low 
Loss Cable, 1/6 yd. U.H.F. 1'reamps from 
75/-. State clearly channel number required 
on all orders. 

BBC • ITV AERIALS 

BBC (Band 1). Tele- 
scopic loft, 35/-. External 
S/D. 30/-. "H" £2.15.0. 
I iv (Baud 3). 3 ele- 
ment loft array. 30/-. 5 
element, 40/-. 7 element, 
50/-. Wall mounting, 3 ele- 
ment. 47/6. 5 element. 
52/6. Com hi ii i<d itBC/ 
ITV. Loft It- 3, 40/-; 1+5. 
60/-: 1+7. 60/-: Wall 
mounting 143, 57/6; 1*5, 
67/6; Chimney 1-3. 87/6; 
1^-5.75/-. 

VII F transistor pre- 
amps, 75/-. 

COMBIMiD BBC1 — ITV — BBC3 
AIUUALS 1+3 + 9. 70/-. 1+5 + 9, 80/-, 

1+5 + 14, 90/-. 1+7 + 14, 100/-. Loft mounting 
only. Special leaflet available, 
F.M. (Hand 2>. Loft S/D. 15/- "H", 32/6. 
3 element. 55/-, External units available. 
Co-ax. cable 8d, yd, Co-ax. plugs, 1/4, 
Outlet boxes, 5/-. Dlplexer Crossover Boxes. 
13/6. C.W.O. or C.O.D. P. & P. 5/-. Send 6d. 
stamps for illustrated lists. 

Callers welcomed - open all day Saturday 

K.V.A. ELECTRO NECS (Dept. P.W.) 

27 Central Parade, Mew Aldington 

Surrey (CRO-OJB) 

LODGE HILL 2266 




AEKIAL WIRE: Coils of 25 yd. Single Strand 2/3+ 

Sd P, & 1*. 

BELAYS: 

1. Miniature I' lug-In Belays. 185 Colt 4. 5/1 8 V. 

2 Change over Contacts 13/8 + 1/S F, ft P. 
9. Miniature 1* lug-in Belaya. 130 Coil 4, IJght Duty 

CotitaoLi. 9/15V. 18/9+ 1/6 P. ft P. 

3. 6V, octal base A/C Relays. 2 pairs hoary duty 
contacts c/o. Complete wltb octal ba»e,'83/--t- 
1/0 P. ft P. 

4. Single change over Belay. 873 Colt. 18V. lor 
printed circuit, IB/- +1/6 P. ft P. 

5. Base* (or Item 1 and 2, 8/9+6d P. ft P. 
Stat* whether wired or printed circuit. 
TEST METER: 20K per volt ITI-2. £8.6.6, 
PT34 small test meter Sl.14.0+3/- P. ft P. 
TAYLOR Jun. £10.10.0. AVO Minor £8.10,0, and 
many others. 

LOUDSPEAKERS: 8 OHM 2" to 5" irom 7/0 to 13/6 

+ 1/6 P. A P. 

CsrSrwakers 7" x 4" 13/6 + 2/- P, ft P. 

TRANSFORMERS: 260-0-200 ate, 00 M/A/6-3V. 

18/8 + 3/0 P. &1*. 

250-0-250 «c, 100 M/A/8-SV. 39/8+3/0 P. ft P. 

TRANSFORMERS SUITABLE FOR SMALL POWER 

SUPPLIES: 5/11/17V at 4 ainpa. 27/8+3/6 P. A 

P. 3 to 30V tapped 2 amps. 80/-+ 3/8 P, ft P. 

0-9-1 5 V. It amps. 16/6+3/- P. ft P. 75 W auto 

transformers. 10/8 -r'i'O P. ft P. 

OUTPUT TRANSFORMERS : Suitable (or EL807 UL84 

Singles. 6/6 -i 2/5 P. k P. Midget Choke Output. 6/8 

+ 2/6 P. ft P. 

CONDENSERS ELECTROLYTIC: 2, 4, 10, 18, 30 50, 

100m.a.il. I5V. I/6 + 4M, P. ft P.ench. 

CARBON CONTROLS: 5K to 2M Lin. or Log. 3/9 

+ 1/- P. ft P. 5K lo 2M Lin. or Log. with s/W, 5/8 

+1/-P, ft P. 

EAR PIECES: 2-5 mm or 3-5 mm Magnetic 8/6, 

Crystal 2-3 mm, 3'5 mm. 5/6. 

SINCLAIR PRODUCTS: All unit* and Mat. Trans. 

TRANSISTORS: Popular Range OC44, OC45, OC71, 

OC72, OtHSl, 0O2, all at 2/6. 

POWER TRANSISTORS: OC2G, 10/9, OC2S 15/8. 

0088. 13/6. ADTH9. 15/-. 

QSMOR RANGE <>[ ll-'s.o.jh, Driver ft output trans. 

ELECTRONIC EFTS: Suitable tor beginners £2.17.8. 

Write or call lor our ttce Component* List. 

BOTH WELL ELECTRIC 
SUPPLIES ; Glasgow) LTD. 
54 EGLINTON STREET 
0LASO0W, C.5. Tel. 041 SOUth B904. 

Member ol the Lander Group 




222 



Fully guaranteed 
Individually packed 

VALVES 



PERSONAL CALLERS WELCOME 
Open 9.30-12.30, 1.30-5.30 p.m. Thursday 9-1 p.m. 

VLASY OTHERS IN STOCK include Cathode Ray Tubes and Special Valves. V E Orders 
np to 10/-. 1/-; 10/- to £1, 2/-; over £1, 8/- per il; over 43 post !tee. C.O.D. 4/- extra 



AC/HI. 8/- 
ALS0 S/- 
Altl';i 3/- 
ARP12 3/6 
ARS 5/- 
AKTF1 8/- 
ATP4 8/3 
AZ31 10/8 
BH7* 40/- 
BL63 10/- 
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BTM 55/- 
BT4S 150/- 
BT83 35/- 
CVJ02 1/- 
CV10S 4/- 
CV3 15 (mat- 
ched pair) 

120/- 
CV315 (Sin- 
gle) 50/- 
«Y31 7/6 
mi 6/- 
1>77 8/- 
DA100 £8 
liAl-'tM 6/- 
1)1)41 41- 
DBT20 2/- 
0SO3B 10/- 
DF81 8/ 



1 1 [ !!■ 

n Km; 
DKfla 

DK'Jii 
1)1.1 W 
DI.W 

!)].;« 

[J1.H4 

DUNJ 

Ds.su:;. 9/6 

DYftS 6/9 

DY87 7/- 

Ksnl-' 18/- 

E88CC 8/- 

i;:''"i.i: 10/- 

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EAi'M-i 9/e 

!-;ih»i 2/- 

EBC33 8/- 

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■a |3 m 

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EC53 12/8 

UC70 4/- 

KC90 4/- 

If.n 3/ 

eccju 12/- 

ECT31 4/- 

EiVs'J 4/3 

n ess a/a 

ECC84 6/- 

Kf'cs.-) 5/4 

ECC88 7/- 

BOC91 4/- 

i-;ni<:i a/g 

K< ■]■'-" 7/8 

JKWSB 7/6 

EC 11:15 11/- 



ECH42 10/6 
ECU81 5/9 
D.'Hvi s/6 
ECL80 6/B 
ECLS2 10/8 
ECL83 10/8 
BGL86 873 
Er'36 3/4 
EF37A 8/ 
EE39 6/ 



EF40 
EF41 
HF60 

EF^O 
EFSI 

El-'.-iS 
EFM6 
B I- 88 
EF91 

F.Vit-2 

BFBS 



9/3 
10/- 
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5/3 

8- 

7/6 
8/9 
5/9 

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2/S 

5(9 



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EF184 8/- 

EH90 7/6 

EL31 15/- 

EL3'2 3/9 

ELM 11/- 

ET.35 5/ 



hi.m 

EL41 
E 1,4-2 

F.T.50 
EL81 
RI.M4 
EJA5 
El. ill 
Kl.Ui 
BL364 18/ 

mm s/- 

EJf80 8/- 
ESIS1 8/- 

wam» 8/3 

EM(2 5/- 

ESIT4 80/ 

EY51 8/- 

EYert 7/3 



17/6 
9/3 

11/- 
8/- 
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4/9 
8/8 
2/8 
5/9 



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EZ41 8/- 
EZ80 5/9 
E281 5/3 
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FW4/800 

10/- 
fi/371KS7/6 
O1/370K 

20/- 
G50/-2G &/- 
t; 120 (IB 

17/6 
<JM4 45/- 
(1TE175.M 

12/- 
tJUoO 88/- 
QZ39 11/8 

v.z;u n/a 

H3u 3/6 

HL'2 4/- 

ILL2K S/6 
HL230D5/- 

HU1 4/- 

II V It '2 9/- 

KT8C 22/- 

KTU3 4/- 

KT86 18/6 

KTfJ7 45/- 

KT7 1 7/8 



KT76 
RT8S 27i 
ETZ63 
E63 
MH41 
MHLD6 
MU5 
N34 8 

X75 

OA2 

OB-2 

OE3 

OC3 

OD3 

OZ4A 

P41 

pabcso 8 

peso- 
rcss 

FC97 

PCUdu 

FCC84 

PCC89 10 

POC1S9 12, 

FCF80 

PCF82 

1 , CF84 9 

PCF86 9 

PCES01 9 

PCF802 10, 

PCF80S 12, 

PCF80814, 

PCM I 10 

PCLS2 

P01j83 

PCL84 8 

POL8S 

PCL86 

PFL29014 

FL3S 

PL3-- 

PLS1 

FLS-2 

Pl-i?E 

VIM 

PW00 15 

PX4 

l'X25 

PYJ 

PYSO 

PVS1 

FY 82 

FY83 

PY800 10, 

PY801 10, 

QQVO3-10 

2T 
QQVO6-40 

S" 
QQYOS- 

40 A 100, 
QS15013 

QS95'10 5, 
QS 1-2(1(1 10 
QS 120*2 8, 
QV04 ~ " 
B10 
BG1/240A 

SPS1 

STV-S3'4(> 

34 

SU2150A 



25 12l 



- J TDOX-20 

70/- 
TP2"2 5/- 
TP-25 5/- 
TTU 31- 
1115 35/- 
TTB31 45/- 
TZ40 40/- 
TZOd^O 41- 
TZ20 16/- 
U12/14 71- 

ris «/- 

L2S 16/- 

i:-2fi 16/- 

U27 8/- 

U52 4/8 

181 18/- 

t T 19l 16/- 



VP133 


9/- 


YB09 


7/8 


VR1O5/30 




8/- 


\ KloO/30 




6/- 


1T"39 


71- 


W118 


10/- 


W119 


9/- 


X65 


5/ 


SOI] 


7/6 


X7I-M 


71- 


X118 


8/ 


XI45 


8/- 


Y63 


B/6 


YBG 


■5/ 


Z800L" 


20/ 


ZSOIU 


20/- 



Z900T 


121- 


i naa 


30/- 


i c.-.i ;i 


«/- 


1D8GT 


8/- 


H;t3i;T 


8/- 


ISA 


8/8 


1EA6 


«/- 


lLCfi 


71- 


II. ill 


V- 


IRS 


6/- 


1S4 


b/- 


IBS 


4/6 


1T4 


3/ 


2A3 


5/- 


21)21 


4/9 


;:.-\4 


4/ 


3A108A 


35/ 


3A14BJ 55/- 



;;a i.j7 m 

55/- 



3B7 

3Bl!4 
3 DO 
3E-29 
3Q4 



SI- 
14/- 
8/- 

50/- 
8/ 



3QBGT 6/- 
884 a/9 

8V4 6/6 

41)1 4/- 

6A173G 61- 
0A174C 61- 
SI«.-iEV40/ 
..l'.'.-.v./'l3o/ 
BB2SSM15/ 

ou*i4.vr40/ 
r>BBS5MS6/- 



5R4«Y 


w- 


5T4 


71- 


Jl.'4li 


4/8 


5\'4U 


7/H 


5X4G 


8/6 


BY3GT 


5/9 


5Y3WGTB 




9/- 


6Z4G 


7/3 


■1AI.W 


41- 


0AC7 


3f- 


f'.AGS 


8/8 


UAG7 


8/- 


riAH'.i 


10/- 


HA.F7 


th 


HAKo 


87- 


6AK.7 


B/- 


tiAKH 


5/9 



8AXS 3/- 

6AE5W 7/- 
GAM5 3/6 
6AiI6 3/- 
6 AX S 5/6 
6AXSW 9/- 
8AS6 6/- 
6AS7G 14/- 
AAT6 4/6 
6AL'6 5/9 
6 AX 4 8/- 
6B4G 15/- 
5/6 



6B8G 

SBAfl 
fiBA7 
I5BKU 

(SBJ8 



2/6 
4/6 
12/6 
5/3 
8/6 



TRANSISTORS, ZENER DIODES etc. 



OAS 

OAin 

OA47 
OAT9 
OA81 
OA90 



OA'200 2/6 
OA202 3/6 
OA2I0 7/6 
0A211 9/6 
OAZ20011/- 
OAZ20110/- 
OAZ3Q2 
to 

OAzaofi 8/6 

OAZ-207 9/6 
OAZ208 



OAZ'22510/- 
OC18 15/- 



OC22 

oe23 

0O24 
OD25 
OC28 



10/- 
12/6 
15/- 
7/8 
B/- 



OC28 
OC3ij 
OC41 
OC70 

OC71 
OC72 
OC73 

OO70 



12/8 
10/- 
6/- 
4/- 
8/- 
5/- 
B/- 
»- 



OC81D 8/- 

OC82 5/- 

OC139 7/8 

OC189 6/- 

OC170 51- 

OC200 7/0 

OC201 10/- 

OC*-202 12/B 

OC203 10/6 

OC-204 17/6 

OC200 IB/6 

OU206 17/6 

IN21 3/8 
IMaiB 
IN43 



ES70 
IS1U 
1SU3 
IS US 
2X585 



5/- 
--!/- 

S- 

4/ 
■1/fi 
8,'- 
7/8 



-JNHHii 


20/- 


2N1UIM) 


7/6 


UN 1091 


9/6 


2N1808 


7/B 


2M:!()7 


7/6 


*2S;i03 


10/ 


AAZ18 


4/- 


AC107 


10/- 


Ari2i! 


6/6 


AC 1-27 


7/8 


AC 128 


8/B 


ACJ76 


7/6 


ACY17 


8/6 


ACY18 


6/6 


ACY19 


6/6 


ACY20 


5/- 


ACY21 


8/- 


AC Y 2*2 


3/6 


ACY28 


4/6 


Aliiln 


18/- 


A l.> MS 


18/- 


AEY1I 


15/- 


AEY12 


18/8 


A PI 02 


18/- 


AFI14 


B/B 


AFU6 


8/- 


AF1I6 


6/6 


AF118 


10/- 



AE124 


7/6 


AF125 


8/6 


AK12I1 


8/- 


Af-'l'JT 


8/- 


AF130 


10/- 


AF178 


12/8 


Al'VlS 


22/8 


AI'Z.ll 


17/- 


ASVifi 


6/6 


AST38 


6/6 


AHZ'Jl 


12/6 


ASZ23 


30/- 


Al'161 


30/- 


El 'IU7 


6/- 


1 ii ' 1 :■■ 1 


13/3 


I'.i'V;;:-; 


7/6 


IWYW 


«fc 


1WY27 


6/6 


UMY2H 


51- 


ISSV. 1 


7/6 


BYZ10 12/- 


BYiill 


10/6 


BY212 


10/- 


UYZ13 


0/ 


15 \ /.l.i 


80/ 


BVZ1B 


15f- 


CK74 


17/8 


CRSl/lOS/ 



CRai/2fl 9/8 

CR8I/3W 

10/- 

ujfai/ss 

11/6 
CRS1/40 

12/6 
CRS3/0B 6/- 
CRBS/20 

10/- 
CR83/30 

11/8 
CRS3/40 

13/6 
C84B 25/- 
(1ET10-2 6/- 
GBT103 4/6 
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CET1U 9/- 
OET115 9/- 
GETUS 8/8 
GET872 6/- 
GET8H0 9/- 
GEX54 2/8 
LU8M 4/6 
GT43 51- 
JK9A 22/B 



JKIOA 15/- 
JK10B 15/ • 
JKUA 12/8 
JK19A 23/6 
TK20A 17/6 
■TK21A 12/ 8 
MAl'100 7/9 
MAT101 8/6 
MPF102 

H/- 
MPF103 9/6 
MFF104 

10/- 
MPElOo 

10/- 
RASBOSAi" 

12/6 
SOBS I 12/6 
SX645 15/- 

Z lhlliL":- 

Zener diodes 
3/6 each 
Z2A range 

7/6 ea. 
ZB range 

5/-ea. 
ZS range 

7/6 ea. 



17404 


g;- 


rsoi 


h;s 


UABC80 6/- 


LAE42 


j: ,; 


T7BC41 


»/- 


IJBPSfl 


Ifi 


rccf-5 


W 


UCl'80 


a/8 


UCH42 


h;3 


LCH81 


6.-H 


ocLaa 


S;S 


UCL83 


1D/B 


i:F4i 


HlB 


UFB9 


Hi'A 


UL41 
UIJ<4 
Lta 


m 


M- 


UU9 


R|fl 


UY21 


iUrl.) 


LY41 


7/6 


UY8B 


5, '9 


Y246A,'1K 


190/- 


VLS83135/- 


YP23 





P. C. RADIO LTD. 

170 GOLDHAWK RD..W.12 

(01) 743 4946 



DC MOVING COIL METERS 

O-50[aA 2i" round pro), 

200riA 2" round panel Seated 

750-0-75(i.A 2" round plug-In 

1mA 

1mA 

5mA 

5-0-5mA 

10-0-1 0mA 

0-30mA 

50mA 

75mA 

100mA 

100mA 

100mA 



25/- 
22/6 
20/- 
30/- 
27/6 
20/- 
17/6 
IH 
17 6 
25/- 
14/- 
17/6 
17/6 
19/- 



2{ square panel 

2" round panel sealed 

2' round clip fix panel or prol 

H"round panel 

2J" round panel 

21" round panel 

2|" square panel 

21" plug-in 

1i"pro| 

H" round panel 

21" round panel 
29,'41ft. AERIALS each consisting of ten 3ft. Jin. 
dia. tubular screw-In sections. 11ft. (6-sectiOn! whip 
aerial with adaptor to fit the Tin. rod, Insulated base, 
stay ptate and stay assemblies, pegs, reamer, hammer, 
etc. Absolutely brand new and complete ready to 
erect, in canvas hag. £3.9.6. P. A P. 10/6. 
FIELD TELEPHONES TYPE "F" housed In portable 
wooden cases. Excellent for communication in- and 
out-doors for up to 10 mites. For pair Including bat- 
teries and 1,'6th mile field cable on drum. Completely 
new, £6.10,0. Slightly used, £5.10.0. Carriage 10/-. 
TELEPHONE HANDSET. Standard G.P.O. type; 
new 12/-. P. & P. if-, 



6B37 71- 

0BX6 8/- 

6BQ7A 4/- 

6BR7 17/- 

6BR8 5/- 

6BW7 11/8 

ilC4 3/6 

6C1G 8/6 

6C5GT 8/- 

8CH 41- 

6C8G 6/6 

<iCH6 7/- 

I5C21 80/- 

UCLS 9/- 

(5C-W4 13/9 

8823 13/- 

6B6 8/- 

6FSGT 8/- 

6F(iG 4/- 



6F7 

'iF-ic; 

8F1-2 
OF 13 
OF 14 
BF23 



6/- 

51- 
41- 
51- 
51- 

14/9 



[CjMR 



brand 



ALL valves 
guaranteed 



15 



0E>2 

6F33 

fiG'SG 

611 6CT 1 

6H61I 

6J4WA 12! 



BSE 



fiji;w 

6J7G 

6J7M 

6KflGT S 

6K7 

SK7C 

6K7GT 

6KSG 

8K33T 

SK2SG 24' 

6L3G 

GI.tiG 

6LJ>GA 9 

fiLTG 

6L154 

6N7G 

BP25 

087 

S3A7 

6SA7GT 

6SC7 

B3t'7GX 5' 

WH7 

B8H7 

08J7G 

ijaj7GT 8 

68 J 7 

6SK7 

B3L7GT 5' 

6S>7 4, 

68X7GT 4, 

6SQ7GT 6, 

68S7 

6V6G 

fiVr-GT 

6V«M 



6X.4 

exao 

6YBG 
6-3 )L2 14; 
6Z4 
7B7 
7C5 



7T4 
7Z4 
9D2 
9GG 
10P9 
10P 1.4 18/ 
11E2 
12A3 
12ATB 
12 A 17 
12AY8 
I 2A \"7 
12AC7 
I2AT7WA 
5/6 



12AX7 


6/3 


12AT7 


10/6 


12BA6 


B/M 


12BE(! 


5/9 


1-2 BH 7 


3:o 


12C8 


3/- 


12E1 


17/- 


F2H6 


3/- 


12X7GT 6/6 


12K7GT 8/- 


l*2K8M 10/- 


12Q7GT 5/- 


12SC7 


4/8 


128C7 


8/- 


12SH7 


3f- 


1-2SJ7 


41- 


12SK7 


5/6 


123L7GT 




7/- 


I2SN7GT8/ 


)'28K7 


5/- 


1*2 Y4 


2/- 


131)1 


4/- 


13135 


5/6 


14S7 


17/8 


19AQB 


h/M 


19E2 


15/- 


19G3 


40/- 


19G6 


15/- 


19 H4 


65/- 


20 A2 


8W- 


28F4 


22/- 


2SB0GT 7/3 


•20Y5 


6f- 


'25Z4G 


9/3 


25 Zi 


7/8 


25Z4GT 9/8 


25 DT 


6/8 


S0C15 


15/6 


30C17 


15/8 


30C18 


16/- 


30P5 


16/- 


30EL1 


17/3 


30FL12 


19/6 


30FB1J 


9/3 


30FL14 


16/- 


30L15 


17/3 


30L17 


17/3 


30PI2 


14/9 


30P19 


18/- 


30PL3. 


1*/- 


30PL13 18/4 


30PL14 


18/4 


33A101K 




9/- 


33L8GT 7/ 


35T 


17/6 


35W4 


a/- 


35Z3 


11 f3 


35Z4G1 


7/6 


35Z5G1 


B/- 


37 


41- 


38 


41- 


42 


5/6 


;oci!!j.' 


31(6 


50BBG1 


8/6 


37 


8/- 



81 9/- 

83 10/- 

84 5/- 
85A2 8/- 
282 A 100/- 
3(1 7 A 5/8 
310C 25/- 
350B 8/- 
357 A 71- 
3ti8A 5/- 
36 3 AS 80/- 
393A 27/6 



408C 

446A 

703A 

705A 

71SB 

7t7A 

803 

807 

808 

813 

8 13 

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935 

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1625 

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2051 



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If Fit 

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2N706 
2N753 
27S T 1132 37/- 
2N1301 7/- 
2S1304 8/- 
2X1756 15/- 
2X2068 £0/- 
2X236 9 A 4/6 
2X2926 5/6 
2X3819 13/- 
28002 20/- 



2>00:i 
2Svf'4 
28005 
2S006 
23012 
2?'ll- 

as 102 

23103 

2S104 



20/- 
15/- 
50/- 
80/- 
140/- 
60/- 
8/3 
35/- 
15/- 



BUILD AN I.C. AMPLIFIER 

(seePW May iwtie) 
TXTEfiRATED CIRCUIT TYPE CA3020. cquh-aleM to 
seven IramtistflM and 3 diodes. 30/-. P.P. 1/6. 



DRY REED INSERTS 

Glass dry reeii inserts appro*. Jin, dia 1 lln long with 
axinl leads One "mate" contact ol 100mA capftclty at 
B0V Can he operated by permanent magnet or 30-50 
Amp-tums relay colls. PK1CE 18/- per ilea, post tree. 



25 WATT SOLDERING 
IRONS 

200-250 watt exceptionally well made lightweight solder- 
ing irons with polished wooden handles ami chromium 
plated body. Angle hit of sufficient length for long life. 
No breakable plasties used in emistnn-iiuii. ["NICE 16/- 
(P.P. 2/-}. 



THYRISTORS 

3'40, 400 p.i.v. 3 amp, stud mounted. Gate voltage 

30 v, at 20mA max , ... 71Q 

BLUE SPOT, 200 p.l.v. B amp, stud mounted. 

Gate voltage S-2ov. at 120mA ina\- 13/8 



OREEli SPOT. 400 p.l.v. 5 amp, stud 
Gate voltage 3-23v, at 120 mA max. 



iLOini.iML 



17/6 



AVALANCHE SILICON 
RECTIFIERS 

Type KAS308AF, 980 p.Lv. at 8 amps, mas., stud 

mounted , , , , , , 10/6 



WE WANT: Klystrons 723 A IB. 9K3S; Thyristors 4C35, 
BC22: Transmitting valves 845. 4-S5A. Please offer as 
your surplus stock of the above and other special types. 



SPECIAL OFFER OF 
TRANSISTORS 

Germanium General Pnrpose P-N-P Transistors, suitable 
for experiments and in computers. Price as low or lower 
that some diodes. Types 2G371A, 2G381 25/- per doi. 
assorted. 



SILICON ZENER DIODES 

11 watts 5%; 2-4V., 2'7V., JPOV., 3-GY.. 3-9Y., 15>0Y„ 
16-0V..30'0V.— ALL AT 5/6. 

B.j. watts 5" M : :t'0V.,27-0V., :m-i\V., 3K-0V.— ALL AT 6/6. 
10 watts 10%: 4-7V., 6-1V., 6-OV.. 0-2Y., 7-5V., 8-2Y., 
91V,. 12-OV., 14-0V., 150V., 18-OV., 270V., ;;o -n\ '.. 
43-0 V., 47-0 V.— ALL AT 8/6. 



SILICON POWER 
RECTIFIERS 

BYIOO. 700 p.i.v.. 450mA, W.E 4/8 

B VZ 10, .100 p.i.v., 6 Amps. 3. M. . 9/- 

RYZI2. 400 p.l v . 6 Amps, S.J4. . . 5/- 

BYZ13. 200 p.i.v . 6 Amps, S.M. . 7/f 

BYZ19. as BYZ13 hut stud negative 7/8 

W>0ttu. 50 p.i.v., 500mA, W.E 3/ - 

DD006, 400 p.i.v.. 500mA, \V,E. , 6/6 

DD05S, 800 p.*., 500mA, W.E. 7/6 

A'ots: W.E. — Wire Ended, S.M— 8tud Mounted. 



FULL PRICE LIST OF VALVES, CATHODE RAY 
TUBES, SEMICONDUCTORS, ETC, IS AVAILABLE 
FREE OP CHARGE. PLEASE SEND QUARTO S.A.E. 



224 



I PRACTICAL 
1WIRELESS 



blueprints 



The following blueprints are available from stock. Descriptive text is not available but the date of 
issue is shown for each blueprint. Send, preferably, a postal order to cover cost of the blueprint (stamps 
over 6d. unacceptable) to Blueprint Department, Practical Wireless, George Newnes Ltd., Tower House, 
Southampton Street, London, W.C.2. 



The Strand Amplifier 
The PW Signal Generator 



::} 



The Berkeley Loudspeaker Enclo- 
sure 
The Luxembourg Tuner 

The PW Troubadour 
The PW Everest Tuner 

The PW Britannic Two . . 
The PW Mercury Six 

Beginner's Short Wave Two 
S.W. Listener's Guide 

PW "Sixteen" Multirange Meter 
Test Meter Applications Chart 



(Oct. 1962) 5/- 

(Dec. 1962) 5/- 

\ (June 1962) 7/6 

\ (May 1962) 6/- 

\ (Nov. 1963) 5/- 

\ (Jan. 1964) 5/- 



The Celeste 7 -transistor Portable"! 



Radio 

The Spinette Record Player 

Transistor Radio Mains Unit 
7 Mc/s Transceiver 



V (June 1963) 5/- 



} 



(June 1964) 5/- 



The Citizen (December 1961) .. .. .. 5/- 

The Mini-amp (November 1961) . . . . 5/- 

The Beginner's Short Wave Superhet (Dec. 1964) 5/- 

The Empire 7 Three-band Receiver (May 1965) . . 5/- 

Electronic Hawaiian Guitar (June 1965). . . . 5/- 

Progressive SW Superhet (February 1966) . . 5/- 



Beginner's 5- Band Receiver 
Home Intercom Unit 



} 



(Dec. 1966) 5/- 



PLEASE NOTE THAT WE CAN SUPPLY NO BLUEPRINTS OTHER THAN THOSE SHOWN IN 
* THE ABOVE LIST. NOR ARE WE ABLE TO SUPPLY SERVICE SHEETS FOR COMMERCIAL * 

RADIO, TV OR AUDIO EQUIPMENT. 



1 PRACTICAL 
IWIRELESS 



query service 



Before using the query service it is important to read the following notes: 



The PW Query Service is designed primarily to answer 
queries on articles published in the magazine and to deal 
with problems which cannot easily be solved by reference 
to standard text books. In order to prevent unnecessary 
disappointment, prospective users of the service should 
note that: 

(a) We cannot undertake to design equipment or to 
supply wiring diagrams or circuits, to individual require- 
ments. 

(b) We cannot undertake to supply detailed information 
for converting war surplus equipment, or to supply circuitry. 

(c) It is usually impossible to supply information on 
imported domestic equipment owing to the lack of details 
available. 



(d) We regret we are unable to answer technical queries 
over the telephone. 

fej It helps us if queries are clear and concise. 

(f) We cannot guarantee to answer any query not 
accompanied by the current query coupon and a 
stamped addressed envelope. 



QUERY COUPON 

This coupon is available until 5th July, 1968 and 
must accompany all queries in accordance with the 
rules of our Query Service. 

PRACTICAL WIRELESS, JULY 1968 



Published on or about the 7th of each month by GEORGE NEWNES LIMITED. Tower House, Southampton Street, London, W.C.2. at the recommended 

maximum price shown on the cover. Printed In England by WATMOUC ■ i n. my. E-sd.oid; mid London, Sole AcenLs for Australia and New Zealand' 

GORDON & GOTCH (A/sla)Ltd. South Africa : CENTRAL NEWS AGENCY LTD. Rhodesia, Malawi and V.:uu\ila : KING8T0NS LTD. Kasr A->'ir:a : STATIONERY 
& OFFICE SUPFLD3S LTD. Subscription rate including- postage for one year. To any part of the World tl.16.0d. 



SOLID HIGH FIDELITY AUDIO EQUIPMENT British made; 



POWER AMPLIFIERS 



PRE-ANIPLIFIERS/CONTROL UNITS 



POWER SUPPLIES 



r 






$ *% #$ *$- $$ 



* 



4 MPS 



W*«P»^ 



•4 SPt. a 

SP8-2 




16 PAGE BROCHURE ON REQUEST. No 21 
All units sold separately. 



• MPS mono preamplifier/ 
control unit £6.1 9.6 pj> 3/ _ 

• SP4-A mono/stereo version ol 
^3 £11.19.6 pp. 4/8 

• SP6-S mono/stereo (takes mag. 
pick-up as we)]) 

£15.10.0 pp. w _ 

• MPA1E/8 12 watt amplifier 
3 to 5 ohm output 

£4.10.0 p ,p.2,a 

• HPA12/15 13 watt amplifier 

M to 16 ohm £5.5.0 pp9/s 

• MP ASS 25 3('i watt amplifier for 
7 j-18 ohm speaker 

£7.1 0-0 p.p. 3/8 

• PS24/40 power supply ior 
MPA13/3 1 MPA12/15 

£3.12.5 p.p.3/- 

• MU24/40 choke version 

£4.10.0 pp- 3 '« 

• MU60 power supply for 

Mi'.vjs £4.17.6 p-p-*« 



All systems complete with grey silver panels and mate bine silver 
knoll. 

Audio Equipment developed from Hinsdale Mk. II — each unit or 
system will compare favourably with other professional equipment 
selling at much higher prices. Brief details are below : 



Comptets suggested system* 


Price 


LA 


MP3 ~ MPA12/3 + Mf24 


£ 15.6.0 p.p. 6/- 


n 


MPS -5-MPA12/1S +MU40 


116.0.0 p.p. 87- 


4 


MF3 -<2) MPA12/13 +MU40 


tei.e.e p.p. 7/. 


6 


MP3 - MP A25 4- MU6Q 


£18.15.0 p.p. 7/- 


SA 


3P4-A+{2) MFA12/15 + MU40 


£28.0,0 p.p. 8/0 


10 


3PG-2-H2) MPA12/15 -MT'40 


£28.5.0 p.p. 8/8 


ISA 


SP4-A-<2) MPA25+(2) MU60 


185.10.0 p.p. 10/- 


13 


SPB-2 -(•>) MFA2S + (2) MUBO 


(88.17.8 p.p. 10,'- 



THE FINEST VALUE IN HIGH FIDELITY-CHOOSE A 
SYSTEM TO SUIT YOUR NEEDS AND SAVE POUNDS 



COMPLETE RANGE OF SUITABLE PLAYER DECKS, SPEAKERS AND TUNERS IN STOCK. — ASK FOR LATEST LIST 16 • 



NEW 



INTEGRATED 7 WATT AMPLIFIER 
AMD PREAMPLIFIER — MA 7 



New design for 3 to 16 ohm speakers. Input 
lor mas;. seal.' ceramic pa's. Tape, tuner 
mie. etc. Battery operated or mains unit 
Foil Treble/Baas controls. 8 translator 
design. 




PRICE £8.10.0 P.P. 4/- 



Leaflet on request (Mains int PS20 82/6. P.P. 3/- 



WE CAM SUPPLY STOCK FROM MOST 
OP THE PARTS SPECIFIED FOB CIR- 
CUITS IN THIS MAGAZINE. SEND LIST 
FOB QUOTATION. 



MW/LW QUALITY TRAN-f 9 1 ■ C 
SISTOH RADIO TUBES L,,,la,u 
Brochure 5. 



TRANSISTOR CAR RADIO 
Send for Brochure 15 




BRITISH MADE 6-Transurtor MW/LW. 
12 volt 3 watt output. Push-button 
wave-change. Boxed, ready to use with 
Speaker and Baffle. Car fixing kit and 
manufacturers* guarantee. Special Bargain 
Offer. Positive or Negative Earth. 
6 Push-button £10 10 PP 



de-ltuie version 

£11.19.6. Positive or Negative Earth. 



4/6. 



TRANSISTORS -SEMICONDUCTORS 



COMPLETELY NEW 1068 LIST OF 1000 
types available from stock. Send for your 
FREE COPY TODAY. (List No. 36} 
*S.C.R.'s from 5/- 

*F1ELD EFFECT TRANSISTORS from 9/6 
*FOWER TRANSISTORS from 5/- 

■k U I O D E S A N D R ECTI FIER S f r o m 2 < 
30 page ill nitrated brochure aa above includ- 
ing Valves and Quartz Crystals. 1/- past paid. 



GARRARD DECKS 

ALL THE LATEST MODELS 




COMPLETE 
RANGE IN 
FROM £5.19.6 STOCK 

Send lot illustrated brochure 16 & 17 



MAYFAIR 
PORTABLE 



ELECTRONIC 




TOTAL COST TO BUILD 99 GNS. 

As k f o r 8 ro c h ure 9. ( Inc. ludes general organ components) . 
it Build this instrument stage by stage in your own home. 
t*t A truly portable instrument tor all enthusiasts, 
■*r Fully TRANSISTORISED POLYPHONIC. British design. 
•sr Call in for a DEMONSTRATION and see lor yourself. 

13 NOTE PEDAL KIT £18.0.0. p.p. l 



Also READY BUILT AND 
TESTED 128 gns. 
Deferred terms 
available. 

DEPOSIT £36.8.0 and 12 
monthly payments of 
£9. Total £144.8.0. 
KIT ol PARTS Deterred 
terma: -DEPOSIT £20.19.0 
12 monthly payments ol £7. 
TOTAL COST £113.19.0. 



ORGAN COMPONENTS 
We carry a comprehensive 
stock ol organ components 
lor TRANSISTOR AND 
VALVE FREE PHASE 
designs. Lists on request. 




VHP FM TUNER. Ask lor Brochures 3 and 4, 

87/105 Mc/s Transistor Super hat. Geared tuning. 
Terrific quality and sensitivity. Tor valve or 
transistor amplifiers. 4 x Si x 'J tin. Complete with 
dial plate. 5 Milliard Transistors, plus 4 diodes. 

TOTAL COST PR 1 Q R 

TO build to.ia.o p.p.a/s 




^^^KRToTE^oTEll^^^TrocEure^ 
7 Mnllard Transistors. Printed Circuit 
Design with Stereo Indicator. For use with 
any valve or transistor FM. Uses pot 
cores to Mullard design and ger. and silicon 
transistors. As used by B.B.C. and Q.P.O. 

Complete Sit Price £5.19.6 P.P. 3/8 



Build a Quality TAPE RECORDER with MARTIN REC0R0AKITS 

■*■ TWO-TBACE. Deck- £12.10.6. Amplifier 
£17.19.6. Cabinet suit speaker £8.18.6. Com- 
plete kits with MICROPHONE and Tin. 1,200ft. 
tape, spare apool. 

Today's Value £55 36 QIIS. P.P. 22 '3 

* FOUR-TRACK. Deck £15.19.8. AmplitWr 
£13,18.6. Cabinet and speaker £8.18,8. Complete 
kits with MICROPHONE and 7 In. 1.200(1. tape. 
spare spool. 

Today's Value £60 39 CjnS. P.P. 22/6 





7-TBANSISTOR 

MW-LW SUPERHET 

PORTABLE 

New printed circuit design with full power 
output. Fully tunable on both mwilw bauds. 
7 transistors plus diode, push-pull circuit. 
Fitted 5 Inch speaker, large lerrlte aerial 
and Mullard transistors. Eatry to (mild with 
terrific results. All local and Continental 
stations. Size 10 i 7 i 3 1 in. 
TOTAL COST ffi 1 O R 
TO BCTLD *-"• ,B "° 

Send for Brochure 1 



P.P. 4/6 



BUILD THESE PRACTICAL WIRELESS DESIGNS 



CLUBMAN 
(-ESS CHASSIS 
MK I 89/8 

MK II 72/S 

MK III 45/- 

List No. 41 



I.C. F.M. TUNER 

Dec. 1987 

98/6 

Post a/8 

Including RCA CA3014. 
List 40A. 



SWITCHED F.M. 

TUNER 

Aug. 10B7 

77/8 

List SB.' . 



CATALOGUE 



NEW9TH EDITION 
280 pages, 6,000 items 
1,000 illustrations 



it 25 pages of transistors and semiconductor 

devices, valves and crystals. 
ir 200 pages of components and equipment. 
-Ar 60 pages of microphones, decks and Hi-fi 

equipment. 
The most comprehensive — Concise — Clear components 
Catalogue in St. Britain, Complete with 10/- worth 
Discount Vouchers Free with every copy. 



Send today 8/6 ££ 




HENRY'S RADIO LTD. 

Open Monday to Saturday 9 a.m. to 6 p.m. (TKurs 1 p.m.) 



TWO STOP SHOPPING FOR ALL YOUR NEEDS 

303, EDGWARE ROAD, LONDON W.2. 01 -723-10O8/9 
Mail Order Dept. All types of Components and Kits Organ Dept. 
309, EDGWARE ROAD, LONDON W.2. 01-723-6963 
High Fidelity sales, P.A. A. D. test equipment, record decks etc.